21489880 has 32 divisors (see below), whose sum is σ = 48813840. Its totient is φ = 8513920.

The previous prime is 21489877. The next prime is 21489883. The reversal of 21489880 is 8898412.

It is an interprime number because it is at equal distance from previous prime (21489877) and next prime (21489883).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21489883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1770 + ... + 6790.

Almost surely, 2^21489880 is an apocalyptic number.

21489880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21489880 is an abundant number, since it is smaller than the sum of its proper divisors (27323960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21489880 is a wasteful number, since it uses less digits than its factorization.

21489880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5139 (or 5135 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 21489880 is about 4635.7178516385. The cubic root of 21489880 is about 278.0212533136.

The spelling of 21489880 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred eighty".