21534737 has 4 divisors (see below), whose sum is σ = 24611136. Its totient is φ = 18458340.

The previous prime is 21534731. The next prime is 21534743. The reversal of 21534737 is 73743512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21534731) and next prime (21534743).

It is a cyclic number.

It is not a de Polignac number, because 21534737 - 2²⁴ = 4757521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21534731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1538189 + ... + 1538202.

It is an arithmetic number, because the mean of its divisors is an integer number (6152784).

Almost surely, 2^21534737 is an apocalyptic number.

It is an amenable number.

21534737 is a deficient number, since it is larger than the sum of its proper divisors (3076399).

21534737 is an equidigital number, since it uses as much as digits as its factorization.

21534737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3076398.

The product of its digits is 17640, while the sum is 32.

The square root of 21534737 is about 4640.5535230186. The cubic root of 21534737 is about 278.2145618560.

The spelling of 21534737 in words is "twenty-one million, five hundred thirty-four thousand, seven hundred thirty-seven".