21402620 has 12 divisors (see below), whose sum is σ = 44945544. Its totient is φ = 8561040.

The previous prime is 21402593. The next prime is 21402637. The reversal of 21402620 is 2620412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 535046 + ... + 535085.

It is an arithmetic number, because the mean of its divisors is an integer number (3745462).

Almost surely, 2^21402620 is an apocalyptic number.

21402620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21402620 is an abundant number, since it is smaller than the sum of its proper divisors (23542924).

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

21402620 is a wasteful number, since it uses less digits than its factorization.

21402620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1070140 (or 1070138 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21402620 is about 4626.2965750155. The cubic root of 21402620 is about 277.6444395908.

It can be divided in two parts, 21402 and 620, that added together give a palindrome (22022).

The spelling of 21402620 in words is "twenty-one million, four hundred two thousand, six hundred twenty".