21574739 has 4 divisors (see below), whose sum is σ = 22033824. Its totient is φ = 21115656.

The previous prime is 21574687. The next prime is 21574741. The reversal of 21574739 is 93747512.

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 21574739 - 2¹⁶ = 21509203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21574789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 229472 + ... + 229565.

It is an arithmetic number, because the mean of its divisors is an integer number (5508456).

Almost surely, 2^21574739 is an apocalyptic number.

21574739 is a deficient number, since it is larger than the sum of its proper divisors (459085).

21574739 is an equidigital number, since it uses as much as digits as its factorization.

21574739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459084.

The product of its digits is 52920, while the sum is 38.

The square root of 21574739 is about 4644.8615695196. The cubic root of 21574739 is about 278.3867217637.

The spelling of 21574739 in words is "twenty-one million, five hundred seventy-four thousand, seven hundred thirty-nine".