55051621 has 4 divisors (see below), whose sum is σ = 55067200. Its totient is φ = 55036044.

The previous prime is 55051603. The next prime is 55051631. The reversal of 55051621 is 12615055.

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: 12615055 = 5 ⋅2523011.

It is a cyclic number.

It is not a de Polignac number, because 55051621 - 2¹¹ = 55049573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55051631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340 + ... + 10498.

It is an arithmetic number, because the mean of its divisors is an integer number (13766800).

Almost surely, 2^55051621 is an apocalyptic number.

It is an amenable number.

55051621 is a deficient number, since it is larger than the sum of its proper divisors (15579).

55051621 is a wasteful number, since it uses less digits than its factorization.

55051621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15578.

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

The square root of 55051621 is about 7419.6779579710. The cubic root of 55051621 is about 380.4141859694.

Adding to 55051621 its reverse (12615055), we get a palindrome (67666676).

It can be divided in two parts, 550516 and 21, that multiplied together give a triangular number (11560836 = T₄₈₀₈).

The spelling of 55051621 in words is "fifty-five million, fifty-one thousand, six hundred twenty-one".