21391662 has 8 divisors (see below), whose sum is σ = 42783336. Its totient is φ = 7130552.

The previous prime is 21391651. The next prime is 21391703. The reversal of 21391662 is 26619312.

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

21391662 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1782633 + ... + 1782644.

It is an arithmetic number, because the mean of its divisors is an integer number (5347917).

Almost surely, 2^21391662 is an apocalyptic number.

21391662 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21391662 is a wasteful number, since it uses less digits than its factorization.

21391662 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3565282.

The product of its digits is 3888, while the sum is 30.

The square root of 21391662 is about 4625.1121067494. The cubic root of 21391662 is about 277.5970474623.

The spelling of 21391662 in words is "twenty-one million, three hundred ninety-one thousand, six hundred sixty-two".