21972685 has 8 divisors (see below), whose sum is σ = 30134016. Its totient is φ = 15066960.

The previous prime is 21972677. The next prime is 21972689. The reversal of 21972685 is 58627912.

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

It is not a de Polignac number, because 21972685 - 2³ = 21972677 is a prime.

It is a super-2 number, since 2×21972685² = 965597772218450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21972689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 313861 + ... + 313930.

It is an arithmetic number, because the mean of its divisors is an integer number (3766752).

Almost surely, 2^21972685 is an apocalyptic number.

It is an amenable number.

21972685 is a deficient number, since it is larger than the sum of its proper divisors (8161331).

21972685 is an equidigital number, since it uses as much as digits as its factorization.

21972685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627803.

The product of its digits is 60480, while the sum is 40.

The square root of 21972685 is about 4687.5030666657. The cubic root of 21972685 is about 280.0879188195.

The spelling of 21972685 in words is "twenty-one million, nine hundred seventy-two thousand, six hundred eighty-five".