21402120 has 32 divisors (see below), whose sum is σ = 64206720. Its totient is φ = 5707200.

The previous prime is 21402119. The next prime is 21402137. The reversal of 21402120 is 2120412.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21402096 and 21402105.

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, 89056 + ... + 89295.

It is an arithmetic number, because the mean of its divisors is an integer number (2006460).

Almost surely, 2^21402120 is an apocalyptic number.

21402120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21402120 is an abundant number, since it is smaller than the sum of its proper divisors (42804600).

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

21402120 is a wasteful number, since it uses less digits than its factorization.

21402120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178365 (or 178361 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21402120 is about 4626.2425357951. The cubic root of 21402120 is about 277.6422774988.

Adding to 21402120 its reverse (2120412), we get a palindrome (23522532).

The spelling of 21402120 in words is "twenty-one million, four hundred two thousand, one hundred twenty".