21846981 has 8 divisors (see below), whose sum is σ = 31370080. Its totient is φ = 13444272.

The previous prime is 21846961. The next prime is 21846991. The reversal of 21846981 is 18964812.

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

It is not a de Polignac number, because 21846981 - 2⁵ = 21846949 is a prime.

It is a super-2 number, since 2×21846981² = 954581157628722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 560179 = 21846981 / (2 + 1 + 8 + 4 + 6 + 9 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21846901) 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, 280051 + ... + 280128.

It is an arithmetic number, because the mean of its divisors is an integer number (3921260).

Almost surely, 2^21846981 is an apocalyptic number.

It is an amenable number.

21846981 is a deficient number, since it is larger than the sum of its proper divisors (9523099).

21846981 is a wasteful number, since it uses less digits than its factorization.

21846981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560195.

The product of its digits is 27648, while the sum is 39.

The square root of 21846981 is about 4674.0754165931. The cubic root of 21846981 is about 279.5527767099.

The spelling of 21846981 in words is "twenty-one million, eight hundred forty-six thousand, nine hundred eighty-one".