51215521211 has 4 divisors (see below), whose sum is σ = 51216008400. Its totient is φ = 51215034024.

The previous prime is 51215521207. The next prime is 51215521271. The reversal of 51215521211 is 11212551215.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 51215521211 - 2² = 51215521207 is a prime.

It is a super-2 number, since 2×51215521211² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51215521271) 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, 13391 + ... + 320328.

It is an arithmetic number, because the mean of its divisors is an integer number (12804002100).

Almost surely, 2^51215521211 is an apocalyptic number.

51215521211 is a deficient number, since it is larger than the sum of its proper divisors (487189).

51215521211 is a wasteful number, since it uses less digits than its factorization.

51215521211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487188.

The product of its digits is 1000, while the sum is 26.

The spelling of 51215521211 in words is "fifty-one billion, two hundred fifteen million, five hundred twenty-one thousand, two hundred eleven".