51511061655 has 24 divisors (see below), whose sum is σ = 89550809712. Its totient is φ = 27391037184.

The previous prime is 51511061543. The next prime is 51511061669. The reversal of 51511061655 is 55616011515.

It is a happy number.

It is not a de Polignac number, because 51511061655 - 2⁷ = 51511061527 is a prime.

It is a super-2 number, since 2×51511061655² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1683189 + ... + 1713518.

It is an arithmetic number, because the mean of its divisors is an integer number (3731283738).

Almost surely, 2^51511061655 is an apocalyptic number.

51511061655 is a deficient number, since it is larger than the sum of its proper divisors (38039748057).

51511061655 is a wasteful number, since it uses less digits than its factorization.

51511061655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3397055 (or 3397052 counting only the distinct ones).

The product of its (nonzero) digits is 22500, while the sum is 36.

The spelling of 51511061655 in words is "fifty-one billion, five hundred eleven million, sixty-one thousand, six hundred fifty-five".