21037634 has 4 divisors (see below), whose sum is σ = 31556454. Its totient is φ = 10518816.

The previous prime is 21037631. The next prime is 21037649. The reversal of 21037634 is 43673012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19386409 + 1651225 = 4403^2 + 1285^2 .

It is not an unprimeable number, because it can be changed into a prime (21037631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5259407 + ... + 5259410.

Almost surely, 2^21037634 is an apocalyptic number.

21037634 is a deficient number, since it is larger than the sum of its proper divisors (10518820).

21037634 is a wasteful number, since it uses less digits than its factorization.

21037634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10518819.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 21037634 is about 4586.6800629649. The cubic root of 21037634 is about 276.0571277811.

The spelling of 21037634 in words is "twenty-one million, thirty-seven thousand, six hundred thirty-four".