21394457 has 8 divisors (see below), whose sum is σ = 24912576. Its totient is φ = 17991792.

The previous prime is 21394453. The next prime is 21394459. The reversal of 21394457 is 75449312.

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

It is not a de Polignac number, because 21394457 - 2² = 21394453 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21394453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28463 + ... + 29204.

It is an arithmetic number, because the mean of its divisors is an integer number (3114072).

Almost surely, 2^21394457 is an apocalyptic number.

It is an amenable number.

21394457 is a deficient number, since it is larger than the sum of its proper divisors (3518119).

21394457 is an equidigital number, since it uses as much as digits as its factorization.

21394457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57727.

The product of its digits is 30240, while the sum is 35.

The square root of 21394457 is about 4625.4142517184. The cubic root of 21394457 is about 277.6091370630.

The spelling of 21394457 in words is "twenty-one million, three hundred ninety-four thousand, four hundred fifty-seven".