55651021 has 4 divisors (see below), whose sum is σ = 56171232. Its totient is φ = 55130812.

The previous prime is 55650977. The next prime is 55651033. The reversal of 55651021 is 12015655.

55651021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12015655 = 5 ⋅2403131.

It is a cyclic number.

It is not a de Polignac number, because 55651021 - 2⁹ = 55650509 is a prime.

It is a super-2 number, since 2×55651021² = 6194072276684882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55651061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259945 + ... + 260158.

It is an arithmetic number, because the mean of its divisors is an integer number (14042808).

Almost surely, 2^55651021 is an apocalyptic number.

It is an amenable number.

55651021 is a deficient number, since it is larger than the sum of its proper divisors (520211).

55651021 is a wasteful number, since it uses less digits than its factorization.

55651021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520210.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 55651021 is about 7459.9611929286. The cubic root of 55651021 is about 381.7898504214.

Adding to 55651021 its reverse (12015655), we get a palindrome (67666676).

It can be divided in two parts, 5565 and 1021, that multiplied together give a palindrome (5681865).

The spelling of 55651021 in words is "fifty-five million, six hundred fifty-one thousand, twenty-one".