21480981 has 8 divisors (see below), whose sum is σ = 28986720. Its totient is φ = 14147952.

The previous prime is 21480973. The next prime is 21480997. The reversal of 21480981 is 18908412.

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

It is not a de Polignac number, because 21480981 - 2³ = 21480973 is a prime.

It is a super-2 number, since 2×21480981² = 922865089444722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21480931) 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, 42886 + ... + 43383.

It is an arithmetic number, because the mean of its divisors is an integer number (3623340).

Almost surely, 2^21480981 is an apocalyptic number.

It is an amenable number.

21480981 is a deficient number, since it is larger than the sum of its proper divisors (7505739).

21480981 is an equidigital number, since it uses as much as digits as its factorization.

21480981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86355.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 21480981 is about 4634.7579224810. The cubic root of 21480981 is about 277.9828716393.

The spelling of 21480981 in words is "twenty-one million, four hundred eighty thousand, nine hundred eighty-one".