51515121 has 12 divisors (see below), whose sum is σ = 79901232. Its totient is φ = 29437128.

The previous prime is 51515081. The next prime is 51515129. The reversal of 51515121 is 12151515.

It is not a de Polignac number, because 51515121 - 2⁹ = 51514609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (51515129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 175075 + ... + 175368.

It is an arithmetic number, because the mean of its divisors is an integer number (6658436).

Almost surely, 2^51515121 is an apocalyptic number.

It is an amenable number.

51515121 is a deficient number, since it is larger than the sum of its proper divisors (28386111).

51515121 is a wasteful number, since it uses less digits than its factorization.

51515121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350460 (or 350453 counting only the distinct ones).

The product of its digits is 250, while the sum is 21.

The square root of 51515121 is about 7177.4034998738. The cubic root of 51515121 is about 372.0873523042.

Adding to 51515121 its reverse (12151515), we get a palindrome (63666636).

The spelling of 51515121 in words is "fifty-one million, five hundred fifteen thousand, one hundred twenty-one".