21237020 has 24 divisors (see below), whose sum is σ = 50969184. Its totient is φ = 7281216.

The previous prime is 21237011. The next prime is 21237031. The reversal of 21237020 is 2073212.

It is a super-2 number, since 2×21237020² = 902022036960800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21237020.

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, 75707 + ... + 75986.

It is an arithmetic number, because the mean of its divisors is an integer number (2123716).

Almost surely, 2^21237020 is an apocalyptic number.

21237020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21237020 is an abundant number, since it is smaller than the sum of its proper divisors (29732164).

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

21237020 is a wasteful number, since it uses less digits than its factorization.

21237020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151709 (or 151707 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 17.

The square root of 21237020 is about 4608.3641349182. The cubic root of 21237020 is about 276.9265054577.

The spelling of 21237020 in words is "twenty-one million, two hundred thirty-seven thousand, twenty".