21318093 has 16 divisors (see below), whose sum is σ = 31836160. Its totient is φ = 14097888.

The previous prime is 21318091. The next prime is 21318109. The reversal of 21318093 is 39081312.

It is not a de Polignac number, because 21318093 - 2¹ = 21318091 is a prime.

It is a super-2 number, since 2×21318093² = 908922178313298, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 321 + ... + 6537.

It is an arithmetic number, because the mean of its divisors is an integer number (1989760).

Almost surely, 2^21318093 is an apocalyptic number.

It is an amenable number.

21318093 is a deficient number, since it is larger than the sum of its proper divisors (10518067).

21318093 is a wasteful number, since it uses less digits than its factorization.

21318093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6353 (or 6347 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21318093 is about 4617.1520442801. The cubic root of 21318093 is about 277.2784499010.

The spelling of 21318093 in words is "twenty-one million, three hundred eighteen thousand, ninety-three".