21318741 has 32 divisors (see below), whose sum is σ = 34416000. Its totient is φ = 12991104.

The previous prime is 21318733. The next prime is 21318761. The reversal of 21318741 is 14781312.

It is not a de Polignac number, because 21318741 - 2³ = 21318733 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14161 + ... + 15593.

It is an arithmetic number, because the mean of its divisors is an integer number (1075500).

Almost surely, 2^21318741 is an apocalyptic number.

It is an amenable number.

21318741 is a deficient number, since it is larger than the sum of its proper divisors (13097259).

21318741 is a wasteful number, since it uses less digits than its factorization.

21318741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1490 (or 1484 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 21318741 is about 4617.2222168746. Note that the first 4 decimals coincide. The cubic root of 21318741 is about 277.2812593239.

The spelling of 21318741 in words is "twenty-one million, three hundred eighteen thousand, seven hundred forty-one".