15400665681 has 4 divisors (see below), whose sum is σ = 20534220912. Its totient is φ = 10267110452.

The previous prime is 15400665661. The next prime is 15400665691. The reversal of 15400665681 is 18656600451.

15400665681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15400665681 - 2²¹ = 15398568529 is a prime.

It is a super-2 number, since 2×15400665681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (15400665661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2566777611 + ... + 2566777616.

It is an arithmetic number, because the mean of its divisors is an integer number (5133555228).

Almost surely, 2^15400665681 is an apocalyptic number.

It is an amenable number.

15400665681 is a deficient number, since it is larger than the sum of its proper divisors (5133555231).

15400665681 is an equidigital number, since it uses as much as digits as its factorization.

15400665681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5133555230.

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 15400665681 in words is "fifteen billion, four hundred million, six hundred sixty-five thousand, six hundred eighty-one".