21356893 has 8 divisors (see below), whose sum is σ = 22850720. Its totient is φ = 19900080.

The previous prime is 21356891. The next prime is 21356897. The reversal of 21356893 is 39865312.

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 21356893 - 2¹ = 21356891 is a prime.

It is a super-2 number, since 2×21356893² = 912233757226898, 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 (21356891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8055 + ... + 10372.

It is an arithmetic number, because the mean of its divisors is an integer number (2856340).

Almost surely, 2^21356893 is an apocalyptic number.

It is an amenable number.

21356893 is a deficient number, since it is larger than the sum of its proper divisors (1493827).

21356893 is a wasteful number, since it uses less digits than its factorization.

21356893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18507.

The product of its digits is 38880, while the sum is 37.

The square root of 21356893 is about 4621.3518584934. The cubic root of 21356893 is about 277.4465681829.

The spelling of 21356893 in words is "twenty-one million, three hundred fifty-six thousand, eight hundred ninety-three".