21192681 has 8 divisors (see below), whose sum is σ = 28720384. Its totient is φ = 13896720.

The previous prime is 21192671. The next prime is 21192709. The reversal of 21192681 is 18629112.

It is a happy number.

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

It is not a de Polignac number, because 21192681 - 2⁷ = 21192553 is a prime.

It is a super-2 number, since 2×21192681² = 898259455935522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon 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, 57721 + ... + 58086.

It is an arithmetic number, because the mean of its divisors is an integer number (3590048).

Almost surely, 2^21192681 is an apocalyptic number.

It is an amenable number.

21192681 is a deficient number, since it is larger than the sum of its proper divisors (7527703).

21192681 is a wasteful number, since it uses less digits than its factorization.

21192681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115871.

The product of its digits is 1728, while the sum is 30.

The square root of 21192681 is about 4603.5509120678. The cubic root of 21192681 is about 276.7336472721.

The spelling of 21192681 in words is "twenty-one million, one hundred ninety-two thousand, six hundred eighty-one".