21423902 has 16 divisors (see below), whose sum is σ = 33916320. Its totient is φ = 10129152.

The previous prime is 21423863. The next prime is 21423907. The reversal of 21423902 is 20932412.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423907) 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, 1478 + ... + 6710.

It is an arithmetic number, because the mean of its divisors is an integer number (2119770).

Almost surely, 2^21423902 is an apocalyptic number.

21423902 is a deficient number, since it is larger than the sum of its proper divisors (12492418).

21423902 is a wasteful number, since it uses less digits than its factorization.

21423902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5347.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21423902 is about 4628.5961154544. The cubic root of 21423902 is about 277.7364356725.

The spelling of 21423902 in words is "twenty-one million, four hundred twenty-three thousand, nine hundred two".