21402837 has 12 divisors (see below), whose sum is σ = 30957420. Its totient is φ = 14249088.

The previous prime is 21402833. The next prime is 21402839. The reversal of 21402837 is 73820412.

It can be written as a sum of positive squares in 2 ways, for example, as 2792241 + 18610596 = 1671^2 + 4314^2 .

It is not a de Polignac number, because 21402837 - 2² = 21402833 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21402837.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402833) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8989 + ... + 11117.

It is an arithmetic number, because the mean of its divisors is an integer number (2579785).

Almost surely, 2^21402837 is an apocalyptic number.

It is an amenable number.

21402837 is a deficient number, since it is larger than the sum of its proper divisors (9554583).

21402837 is a wasteful number, since it uses less digits than its factorization.

21402837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3252 (or 3249 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21402837 is about 4626.3200278407. The cubic root of 21402837 is about 277.6453779282.

The spelling of 21402837 in words is "twenty-one million, four hundred two thousand, eight hundred thirty-seven".