21037247 has 16 divisors (see below), whose sum is σ = 26790912. Its totient is φ = 16041120.

The previous prime is 21037243. The next prime is 21037259. The reversal of 21037247 is 74273012.

It is a cyclic number.

It is not a de Polignac number, because 21037247 - 2² = 21037243 is a prime.

It is a super-2 number, since 2×21037247² = 885131522678018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21037241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 713 + ... + 6525.

It is an arithmetic number, because the mean of its divisors is an integer number (1674432).

Almost surely, 2^21037247 is an apocalyptic number.

21037247 is a deficient number, since it is larger than the sum of its proper divisors (5753665).

21037247 is a wasteful number, since it uses less digits than its factorization.

21037247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5878.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21037247 is about 4586.6378753941. The cubic root of 21037247 is about 276.0554350248.

The spelling of 21037247 in words is "twenty-one million, thirty-seven thousand, two hundred forty-seven".