21312494 has 8 divisors (see below), whose sum is σ = 36535728. Its totient is φ = 9133920.

The previous prime is 21312493. The next prime is 21312517. The reversal of 21312494 is 49421312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 761147 + ... + 761174.

It is an arithmetic number, because the mean of its divisors is an integer number (4566966).

Almost surely, 2^21312494 is an apocalyptic number.

21312494 is a deficient number, since it is larger than the sum of its proper divisors (15223234).

21312494 is a wasteful number, since it uses less digits than its factorization.

21312494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1522330.

The product of its digits is 1728, while the sum is 26.

The square root of 21312494 is about 4616.5456783184. The cubic root of 21312494 is about 277.2541729019.

The spelling of 21312494 in words is "twenty-one million, three hundred twelve thousand, four hundred ninety-four".