15917421 has 16 divisors (see below), whose sum is σ = 24059840. Its totient is φ = 9279360.

The previous prime is 15917411. The next prime is 15917441. The reversal of 15917421 is 12471951.

It is not a de Polignac number, because 15917421 - 2¹¹ = 15915373 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15917411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10000 + ... + 11481.

It is an arithmetic number, because the mean of its divisors is an integer number (1503740).

Almost surely, 2^15917421 is an apocalyptic number.

It is an amenable number.

15917421 is a deficient number, since it is larger than the sum of its proper divisors (8142419).

15917421 is a wasteful number, since it uses less digits than its factorization.

15917421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21516.

The product of its digits is 2520, while the sum is 30.

The square root of 15917421 is about 3989.6642715898. The cubic root of 15917421 is about 251.5499494349.

The spelling of 15917421 in words is "fifteen million, nine hundred seventeen thousand, four hundred twenty-one".