21540708 has 48 divisors (see below), whose sum is σ = 63826560. Its totient is φ = 6154272.

The previous prime is 21540679. The next prime is 21540709. The reversal of 21540708 is 80704512.

It is a super-2 number, since 2×21540708² = 928004202282528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21540709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13491 + ... + 15002.

It is an arithmetic number, because the mean of its divisors is an integer number (1329720).

Almost surely, 2^21540708 is an apocalyptic number.

21540708 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21540708 is an abundant number, since it is smaller than the sum of its proper divisors (42285852).

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

21540708 is a wasteful number, since it uses less digits than its factorization.

21540708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28513 (or 28505 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21540708 is about 4641.1968284054. The cubic root of 21540708 is about 278.2402732703.

The spelling of 21540708 in words is "twenty-one million, five hundred forty thousand, seven hundred eight".