15511505651681 has 16 divisors (see below), whose sum is σ = 17587790586240. Its totient is φ = 13561710819840.

The previous prime is 15511505651671. The next prime is 15511505651683. The reversal of 15511505651681 is 18615650511551.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15511505651681 is a prime.

It is a super-2 number, since 2×15511505651681² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15511505651683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5842925 + ... + 8072346.

It is an arithmetic number, because the mean of its divisors is an integer number (1099236911640).

Almost surely, 2^{15511505651681} is an apocalyptic number.

It is an amenable number.

15511505651681 is a deficient number, since it is larger than the sum of its proper divisors (2076284934559).

15511505651681 is a wasteful number, since it uses less digits than its factorization.

15511505651681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13919816.

The product of its (nonzero) digits is 900000, while the sum is 50.

The spelling of 15511505651681 in words is "fifteen trillion, five hundred eleven billion, five hundred five million, six hundred fifty-one thousand, six hundred eighty-one".