15723421 has 16 divisors (see below), whose sum is σ = 19070208. Its totient is φ = 12672000.

The previous prime is 15723413. The next prime is 15723443. The reversal of 15723421 is 12432751.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 15723421 - 2³ = 15723413 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15723401) 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, 9021 + ... + 10621.

It is an arithmetic number, because the mean of its divisors is an integer number (1191888).

Almost surely, 2^15723421 is an apocalyptic number.

It is an amenable number.

15723421 is a deficient number, since it is larger than the sum of its proper divisors (3346787).

15723421 is a wasteful number, since it uses less digits than its factorization.

15723421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1692.

The product of its digits is 1680, while the sum is 25.

The square root of 15723421 is about 3965.2769134072. The cubic root of 15723421 is about 250.5238137103.

The spelling of 15723421 in words is "fifteen million, seven hundred twenty-three thousand, four hundred twenty-one".