21057235 has 8 divisors (see below), whose sum is σ = 25468416. Its totient is φ = 16712640.

The previous prime is 21057209. The next prime is 21057241. The reversal of 21057235 is 53275012.

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

It is not a de Polignac number, because 21057235 - 2⁹ = 21056723 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15946 + ... + 17215.

It is an arithmetic number, because the mean of its divisors is an integer number (3183552).

Almost surely, 2^21057235 is an apocalyptic number.

21057235 is a deficient number, since it is larger than the sum of its proper divisors (4411181).

21057235 is a wasteful number, since it uses less digits than its factorization.

21057235 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33293.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 21057235 is about 4588.8162961705. The cubic root of 21057235 is about 276.1428363441.

The spelling of 21057235 in words is "twenty-one million, fifty-seven thousand, two hundred thirty-five".