21457886 has 4 divisors (see below), whose sum is σ = 32186832. Its totient is φ = 10728942.

The previous prime is 21457871. The next prime is 21457939. The reversal of 21457886 is 68875412.

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

It is a Curzon number.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5364470 + ... + 5364473.

It is an arithmetic number, because the mean of its divisors is an integer number (8046708).

Almost surely, 2^21457886 is an apocalyptic number.

21457886 is a deficient number, since it is larger than the sum of its proper divisors (10728946).

21457886 is a wasteful number, since it uses less digits than its factorization.

21457886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10728945.

The product of its digits is 107520, while the sum is 41.

The square root of 21457886 is about 4632.2657523074. The cubic root of 21457886 is about 277.8832126807.

The spelling of 21457886 in words is "twenty-one million, four hundred fifty-seven thousand, eight hundred eighty-six".