21019604 has 12 divisors (see below), whose sum is σ = 37640064. Its totient is φ = 10265304.

The previous prime is 21019601. The next prime is 21019613. The reversal of 21019604 is 40691012.

It is a happy number.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21019604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21019601) 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, 60932 + ... + 61275.

It is an arithmetic number, because the mean of its divisors is an integer number (3136672).

Almost surely, 2^21019604 is an apocalyptic number.

It is an amenable number.

21019604 is a deficient number, since it is larger than the sum of its proper divisors (16620460).

21019604 is a wasteful number, since it uses less digits than its factorization.

21019604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122254 (or 122252 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21019604 is about 4584.7141677535. The cubic root of 21019604 is about 275.9782416510.

The spelling of 21019604 in words is "twenty-one million, nineteen thousand, six hundred four".