21354520 has 32 divisors (see below), whose sum is σ = 52416720. Its totient is φ = 7765120.

The previous prime is 21354451. The next prime is 21354551. The reversal of 21354520 is 2545312.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 21354491 and 21354500.

It is a congruent number.

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, 23827 + ... + 24706.

Almost surely, 2^21354520 is an apocalyptic number.

21354520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21354520 is an abundant number, since it is smaller than the sum of its proper divisors (31062200).

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

21354520 is a wasteful number, since it uses less digits than its factorization.

21354520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48555 (or 48551 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21354520 is about 4621.0951083050. The cubic root of 21354520 is about 277.4362919520.

Adding to 21354520 its reverse (2545312), we get a palindrome (23899832).

The spelling of 21354520 in words is "twenty-one million, three hundred fifty-four thousand, five hundred twenty".