15665614401 has 4 divisors (see below), whose sum is σ = 20887485872. Its totient is φ = 10443742932.

The previous prime is 15665614381. The next prime is 15665614403. The reversal of 15665614401 is 10441656651.

It is a happy number.

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 not a de Polignac number, because 15665614401 - 2¹⁸ = 15665352257 is a prime.

It is a super-2 number, since 2×15665614401² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15665614401.

It is not an unprimeable number, because it can be changed into a prime (15665614403) 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, 2610935731 + ... + 2610935736.

It is an arithmetic number, because the mean of its divisors is an integer number (5221871468).

Almost surely, 2^15665614401 is an apocalyptic number.

It is an amenable number.

15665614401 is a deficient number, since it is larger than the sum of its proper divisors (5221871471).

15665614401 is an equidigital number, since it uses as much as digits as its factorization.

15665614401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5221871470.

The product of its (nonzero) digits is 86400, while the sum is 39.

The spelling of 15665614401 in words is "fifteen billion, six hundred sixty-five million, six hundred fourteen thousand, four hundred one".