51691964961 has 32 divisors (see below), whose sum is σ = 84843996160. Its totient is φ = 27260898624.

The previous prime is 51691964959. The next prime is 51691964963. The reversal of 51691964961 is 16946919615.

It is an interprime number because it is at equal distance from previous prime (51691964959) and next prime (51691964963).

It is not a de Polignac number, because 51691964961 - 2¹ = 51691964959 is a prime.

It is a super-3 number, since 3×51691964961³ (a number of 33 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51691964963) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1726626 + ... + 1756308.

It is an arithmetic number, because the mean of its divisors is an integer number (2651374880).

Almost surely, 2^51691964961 is an apocalyptic number.

It is an amenable number.

51691964961 is a deficient number, since it is larger than the sum of its proper divisors (33152031199).

51691964961 is a wasteful number, since it uses less digits than its factorization.

51691964961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36085.

The product of its digits is 3149280, while the sum is 57.

The spelling of 51691964961 in words is "fifty-one billion, six hundred ninety-one million, nine hundred sixty-four thousand, nine hundred sixty-one".