21702480 has 80 divisors (see below), whose sum is σ = 69471744. Its totient is φ = 5598720.

The previous prime is 21702479. The next prime is 21702491. The reversal of 21702480 is 8420712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21702480.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 5982 + ... + 8898.

Almost surely, 2^21702480 is an apocalyptic number.

21702480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21702480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34735872).

21702480 is an abundant number, since it is smaller than the sum of its proper divisors (47769264).

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

21702480 is a wasteful number, since it uses less digits than its factorization.

21702480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2964 (or 2958 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21702480 is about 4658.5920619861. The cubic root of 21702480 is about 278.9350705139.

The spelling of 21702480 in words is "twenty-one million, seven hundred two thousand, four hundred eighty".