51255891 has 12 divisors (see below), whose sum is σ = 77255568. Its totient is φ = 32684784.

The previous prime is 51255887. The next prime is 51255899. The reversal of 51255891 is 19855215.

It is a happy number.

51255891 is a `hidden beast` number, since 5 + 12 + 558 + 91 = 666.

It is not a de Polignac number, because 51255891 - 2² = 51255887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51255899) 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, 123600 + ... + 124013.

It is an arithmetic number, because the mean of its divisors is an integer number (6437964).

Almost surely, 2^51255891 is an apocalyptic number.

51255891 is a deficient number, since it is larger than the sum of its proper divisors (25999677).

51255891 is a wasteful number, since it uses less digits than its factorization.

51255891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247642 (or 247639 counting only the distinct ones).

The product of its digits is 18000, while the sum is 36.

The square root of 51255891 is about 7159.3219651026. The cubic root of 51255891 is about 371.4621737210.

The spelling of 51255891 in words is "fifty-one million, two hundred fifty-five thousand, eight hundred ninety-one".