21037725 has 36 divisors (see below), whose sum is σ = 39087776. Its totient is φ = 11216880.

The previous prime is 21037703. The next prime is 21037727. The reversal of 21037725 is 52773012.

It is not a de Polignac number, because 21037725 - 2²¹ = 18940573 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21037727) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4344 + ... + 7806.

Almost surely, 2^21037725 is an apocalyptic number.

21037725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21037725 is a deficient number, since it is larger than the sum of its proper divisors (18050051).

21037725 is an equidigital number, since it uses as much as digits as its factorization.

21037725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3488 (or 3471 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21037725 is about 4586.6899829834. The cubic root of 21037725 is about 276.0575258164.

The spelling of 21037725 in words is "twenty-one million, thirty-seven thousand, seven hundred twenty-five".