21980957 has 8 divisors (see below), whose sum is σ = 22371384. Its totient is φ = 21593088.

The previous prime is 21980947. The next prime is 21980969. The reversal of 21980957 is 75908912.

It can be written as a sum of positive squares in 4 ways, for example, as 256036 + 21724921 = 506^2 + 4661^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21980957 - 2¹⁴ = 21964573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21980947) 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, 25343 + ... + 26195.

It is an arithmetic number, because the mean of its divisors is an integer number (2796423).

Almost surely, 2^21980957 is an apocalyptic number.

It is an amenable number.

21980957 is a deficient number, since it is larger than the sum of its proper divisors (390427).

21980957 is an equidigital number, since it uses as much as digits as its factorization.

21980957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 21980957 is about 4688.3853297271. The cubic root of 21980957 is about 280.1230624017.

The spelling of 21980957 in words is "twenty-one million, nine hundred eighty thousand, nine hundred fifty-seven".