51015921 has 16 divisors (see below), whose sum is σ = 74486208. Its totient is φ = 30801600.

The previous prime is 51015907. The next prime is 51015949. The reversal of 51015921 is 12951015.

It is not a de Polignac number, because 51015921 - 2⁶ = 51015857 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51015891 and 51015900.

It is not an unprimeable number, because it can be changed into a prime (51015221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6351 + ... + 11931.

It is an arithmetic number, because the mean of its divisors is an integer number (4655388).

Almost surely, 2^51015921 is an apocalyptic number.

It is an amenable number.

51015921 is a deficient number, since it is larger than the sum of its proper divisors (23470287).

51015921 is a wasteful number, since it uses less digits than its factorization.

51015921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5872.

The product of its (nonzero) digits is 450, while the sum is 24.

The square root of 51015921 is about 7142.5430345221. The cubic root of 51015921 is about 370.8815623956.

Adding to 51015921 its reverse (12951015), we get a palindrome (63966936).

The spelling of 51015921 in words is "fifty-one million, fifteen thousand, nine hundred twenty-one".