21192239 has 4 divisors (see below), whose sum is σ = 22307640. Its totient is φ = 20076840.

The previous prime is 21192233. The next prime is 21192247. The reversal of 21192239 is 93229112.

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

It is a cyclic number.

It is not a de Polignac number, because 21192239 - 2⁸ = 21191983 is a prime.

It is a super-2 number, since 2×21192239² = 898221987666242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21192233) 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, 557672 + ... + 557709.

It is an arithmetic number, because the mean of its divisors is an integer number (5576910).

Almost surely, 2^21192239 is an apocalyptic number.

21192239 is a deficient number, since it is larger than the sum of its proper divisors (1115401).

21192239 is a wasteful number, since it uses less digits than its factorization.

21192239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1115400.

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

The square root of 21192239 is about 4603.5029053971. The cubic root of 21192239 is about 276.7317233827.

The spelling of 21192239 in words is "twenty-one million, one hundred ninety-two thousand, two hundred thirty-nine".