15994902421 has 8 divisors (see below), whose sum is σ = 16946587584. Its totient is φ = 15044418240.

The previous prime is 15994902347. The next prime is 15994902437. The reversal of 15994902421 is 12420949951.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15994902421 is a prime.

It is a super-2 number, since 2×15994902421² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15994909421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 272745 + ... + 326158.

It is an arithmetic number, because the mean of its divisors is an integer number (2118323448).

Almost surely, 2^15994902421 is an apocalyptic number.

It is an amenable number.

15994902421 is a deficient number, since it is larger than the sum of its proper divisors (951685163).

15994902421 is a wasteful number, since it uses less digits than its factorization.

15994902421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600491.

The product of its (nonzero) digits is 233280, while the sum is 46.

The spelling of 15994902421 in words is "fifteen billion, nine hundred ninety-four million, nine hundred two thousand, four hundred twenty-one".