21707385 has 32 divisors (see below), whose sum is σ = 42031872. Its totient is φ = 9338880.

The previous prime is 21707359. The next prime is 21707393. The reversal of 21707385 is 58370712.

It is not a de Polignac number, because 21707385 - 2⁶ = 21707321 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4296 + ... + 7865.

It is an arithmetic number, because the mean of its divisors is an integer number (1313496).

Almost surely, 2^21707385 is an apocalyptic number.

It is an amenable number.

21707385 is a deficient number, since it is larger than the sum of its proper divisors (20324487).

21707385 is a wasteful number, since it uses less digits than its factorization.

21707385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12193.

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 21707385 is about 4659.1184788541. The cubic root of 21707385 is about 278.9560830658.

The spelling of 21707385 in words is "twenty-one million, seven hundred seven thousand, three hundred eighty-five".