21980457 has 16 divisors (see below), whose sum is σ = 33615360. Its totient is φ = 14180400.

The previous prime is 21980449. The next prime is 21980461. The reversal of 21980457 is 75408912.

It is not a de Polignac number, because 21980457 - 2³ = 21980449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21980437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12294 + ... + 13967.

It is an arithmetic number, because the mean of its divisors is an integer number (2100960).

Almost surely, 2^21980457 is an apocalyptic number.

21980457 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21980457 is a deficient number, since it is larger than the sum of its proper divisors (11634903).

21980457 is a wasteful number, since it uses less digits than its factorization.

21980457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26301 (or 26295 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 21980457 is about 4688.3320061617. The cubic root of 21980457 is about 280.1209384027.

The spelling of 21980457 in words is "twenty-one million, nine hundred eighty thousand, four hundred fifty-seven".