21752387 has 4 divisors (see below), whose sum is σ = 21945000. Its totient is φ = 21559776.

The previous prime is 21752383. The next prime is 21752429. The reversal of 21752387 is 78325712.

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

It is a cyclic number.

It is not a de Polignac number, because 21752387 - 2² = 21752383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21752383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96137 + ... + 96362.

It is an arithmetic number, because the mean of its divisors is an integer number (5486250).

Almost surely, 2^21752387 is an apocalyptic number.

21752387 is a deficient number, since it is larger than the sum of its proper divisors (192613).

21752387 is a wasteful number, since it uses less digits than its factorization.

21752387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192612.

The product of its digits is 23520, while the sum is 35.

The square root of 21752387 is about 4663.9454327854. The cubic root of 21752387 is about 279.1487197591.

The spelling of 21752387 in words is "twenty-one million, seven hundred fifty-two thousand, three hundred eighty-seven".