21754981 has 8 divisors (see below), whose sum is σ = 22958720. Its totient is φ = 20557152.

The previous prime is 21754961. The next prime is 21754991. The reversal of 21754981 is 18945712.

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 21754981 - 2¹¹ = 21752933 is a prime.

It is a super-2 number, since 2×21754981² = 946558396620722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21754981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21754961) 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, 7561 + ... + 10033.

It is an arithmetic number, because the mean of its divisors is an integer number (2869840).

Almost surely, 2^21754981 is an apocalyptic number.

It is an amenable number.

21754981 is a deficient number, since it is larger than the sum of its proper divisors (1203739).

21754981 is a wasteful number, since it uses less digits than its factorization.

21754981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2955.

The product of its digits is 20160, while the sum is 37.

The square root of 21754981 is about 4664.2235152274. The cubic root of 21754981 is about 279.1598155988.

The spelling of 21754981 in words is "twenty-one million, seven hundred fifty-four thousand, nine hundred eighty-one".