21956685 has 16 divisors (see below), whose sum is σ = 36980160. Its totient is φ = 11093760.

The previous prime is 21956621. The next prime is 21956687. The reversal of 21956685 is 58665912.

It is not a de Polignac number, because 21956685 - 2⁶ = 21956621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21956687) 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 15 ways as a sum of consecutive naturals, for example, 38236 + ... + 38805.

It is an arithmetic number, because the mean of its divisors is an integer number (2311260).

Almost surely, 2^21956685 is an apocalyptic number.

It is an amenable number.

21956685 is a deficient number, since it is larger than the sum of its proper divisors (15023475).

21956685 is a wasteful number, since it uses less digits than its factorization.

21956685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77068.

The product of its digits is 129600, while the sum is 42.

The square root of 21956685 is about 4685.7960903138. The cubic root of 21956685 is about 280.0199178008.

The spelling of 21956685 in words is "twenty-one million, nine hundred fifty-six thousand, six hundred eighty-five".