21192691 has 8 divisors (see below), whose sum is σ = 22861440. Its totient is φ = 19529472.

The previous prime is 21192671. The next prime is 21192709. The reversal of 21192691 is 19629112.

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

It is a cyclic number.

It is not a de Polignac number, because 21192691 - 2¹⁵ = 21159923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21192641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10275 + ... + 12163.

It is an arithmetic number, because the mean of its divisors is an integer number (2857680).

Almost surely, 2^21192691 is an apocalyptic number.

21192691 is a deficient number, since it is larger than the sum of its proper divisors (1668749).

21192691 is a wasteful number, since it uses less digits than its factorization.

21192691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2765.

The product of its digits is 1944, while the sum is 31.

The square root of 21192691 is about 4603.5519981857. The cubic root of 21192691 is about 276.7336907987.

The spelling of 21192691 in words is "twenty-one million, one hundred ninety-two thousand, six hundred ninety-one".