21534504 has 16 divisors (see below), whose sum is σ = 53836320. Its totient is φ = 7178160.

The previous prime is 21534503. The next prime is 21534511. The reversal of 21534504 is 40543512.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 897271 = 21534504 / (2 + 1 + 5 + 3 + 4 + 5 + 0 + 4).

It is not an unprimeable number, because it can be changed into a prime (21534503) 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, 448612 + ... + 448659.

It is an arithmetic number, because the mean of its divisors is an integer number (3364770).

Almost surely, 2^21534504 is an apocalyptic number.

21534504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21534504 is an abundant number, since it is smaller than the sum of its proper divisors (32301816).

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

21534504 is a wasteful number, since it uses less digits than its factorization.

21534504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897280 (or 897276 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 21534504 is about 4640.5284181869. The cubic root of 21534504 is about 278.2135584504.

The spelling of 21534504 in words is "twenty-one million, five hundred thirty-four thousand, five hundred four".