21957458 has 4 divisors (see below), whose sum is σ = 32936190. Its totient is φ = 10978728.

The previous prime is 21957431. The next prime is 21957473. The reversal of 21957458 is 85475912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15108769 + 6848689 = 3887^2 + 2617^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5489363 + ... + 5489366.

Almost surely, 2^21957458 is an apocalyptic number.

21957458 is a deficient number, since it is larger than the sum of its proper divisors (10978732).

21957458 is a wasteful number, since it uses less digits than its factorization.

21957458 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10978731.

The product of its digits is 100800, while the sum is 41.

The square root of 21957458 is about 4685.8785729039. The cubic root of 21957458 is about 280.0232038593.

The spelling of 21957458 in words is "twenty-one million, nine hundred fifty-seven thousand, four hundred fifty-eight".