21653004 has 24 divisors (see below), whose sum is σ = 52154368. Its totient is φ = 6984720.

The previous prime is 21652997. The next prime is 21653011. The reversal of 21653004 is 40035612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21652997) and next prime (21653011).

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, 28732 + ... + 29475.

Almost surely, 2^21653004 is an apocalyptic number.

It is an amenable number.

21653004 is an abundant number, since it is smaller than the sum of its proper divisors (30501364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21653004 is a wasteful number, since it uses less digits than its factorization.

21653004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58245 (or 58243 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21653004 is about 4653.2788439981. The cubic root of 21653004 is about 278.7229428046.

Adding to 21653004 its reverse (40035612), we get a palindrome (61688616).

The spelling of 21653004 in words is "twenty-one million, six hundred fifty-three thousand, four".