21221423204 has 24 divisors (see below), whose sum is σ = 39682815480. Its totient is φ = 9894928896.

The previous prime is 21221423189. The next prime is 21221423219. The reversal of 21221423204 is 40232412212.

It is an interprime number because it is at equal distance from previous prime (21221423189) and next prime (21221423219).

It can be written as a sum of positive squares in 4 ways, for example, as 7948079104 + 13273344100 = 89152^2 + 115210^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21221423204.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1424147 + ... + 1438970.

It is an arithmetic number, because the mean of its divisors is an integer number (1653450645).

Almost surely, 2^21221423204 is an apocalyptic number.

It is an amenable number.

21221423204 is a deficient number, since it is larger than the sum of its proper divisors (18461392276).

21221423204 is a wasteful number, since it uses less digits than its factorization.

21221423204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2863247 (or 2863245 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21221423204 its reverse (40232412212), we get a palindrome (61453835416).

The spelling of 21221423204 in words is "twenty-one billion, two hundred twenty-one million, four hundred twenty-three thousand, two hundred four".