21037970 has 8 divisors (see below), whose sum is σ = 37868364. Its totient is φ = 8415184.

The previous prime is 21037967. The next prime is 21038009. The reversal of 21037970 is 7973012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20693401 + 344569 = 4549^2 + 587^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon 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, 1051889 + ... + 1051908.

Almost surely, 2^21037970 is an apocalyptic number.

21037970 is a deficient number, since it is larger than the sum of its proper divisors (16830394).

21037970 is a wasteful number, since it uses less digits than its factorization.

21037970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2103804.

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 21037970 is about 4586.7166906187. The cubic root of 21037970 is about 276.0585974442.

The spelling of 21037970 in words is "twenty-one million, thirty-seven thousand, nine hundred seventy".