51553021 has 4 divisors (see below), whose sum is σ = 55518652. Its totient is φ = 47587392.

The previous prime is 51553013. The next prime is 51553063. The reversal of 51553021 is 12035515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12035515 = 5 ⋅2407103.

It can be written as a sum of positive squares in 2 ways, for example, as 15912121 + 35640900 = 3989^2 + 5970^2 .

It is a cyclic number.

It is not a de Polignac number, because 51553021 - 2³ = 51553013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51552983 and 51553001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51553081) 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, 1982796 + ... + 1982821.

It is an arithmetic number, because the mean of its divisors is an integer number (13879663).

Almost surely, 2^51553021 is an apocalyptic number.

It is an amenable number.

51553021 is a deficient number, since it is larger than the sum of its proper divisors (3965631).

51553021 is a wasteful number, since it uses less digits than its factorization.

51553021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3965630.

The product of its (nonzero) digits is 750, while the sum is 22.

The square root of 51553021 is about 7180.0432449951. The cubic root of 51553021 is about 372.1785789411.

Adding to 51553021 its reverse (12035515), we get a palindrome (63588536).

The spelling of 51553021 in words is "fifty-one million, five hundred fifty-three thousand, twenty-one".