21790080 has 256 divisors, whose sum is σ = 83966400. Its totient is φ = 5308416.

The previous prime is 21790079. The next prime is 21790091. The reversal of 21790080 is 8009712.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 31 ways as a sum of consecutive naturals, for example, 224592 + ... + 224688.

Almost surely, 2^21790080 is an apocalyptic number.

21790080 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 21790080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41983200).

21790080 is an abundant number, since it is smaller than the sum of its proper divisors (62176320).

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

21790080 is a wasteful number, since it uses less digits than its factorization.

21790080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 21790080 is about 4667.9845758100. The cubic root of 21790080 is about 279.3098650008.

Adding to 21790080 its reverse (8009712), we get a palindrome (29799792).

It can be divided in two parts, 21 and 790080, that multiplied together give a triangular number (16591680 = T₅₇₆₀).

The spelling of 21790080 in words is "twenty-one million, seven hundred ninety thousand, eighty".