21391292 has 12 divisors (see below), whose sum is σ = 40314456. Its totient is φ = 9872880.

The previous prime is 21391267. The next prime is 21391301. The reversal of 21391292 is 29219312.

It is a plaindrome in base 16.

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, 205634 + ... + 205737.

It is an arithmetic number, because the mean of its divisors is an integer number (3359538).

Almost surely, 2^21391292 is an apocalyptic number.

It is an amenable number.

21391292 is a deficient number, since it is larger than the sum of its proper divisors (18923164).

21391292 is a wasteful number, since it uses less digits than its factorization.

21391292 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411388 (or 411386 counting only the distinct ones).

The product of its digits is 1944, while the sum is 29.

The square root of 21391292 is about 4625.0721075460. The cubic root of 21391292 is about 277.5954469711.

The spelling of 21391292 in words is "twenty-one million, three hundred ninety-one thousand, two hundred ninety-two".