21941580 has 72 divisors (see below), whose sum is σ = 64904112. Its totient is φ = 5537664.

The previous prime is 21941573. The next prime is 21941581. The reversal of 21941580 is 8514912.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21941581) 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 23 ways as a sum of consecutive naturals, for example, 21154 + ... + 22166.

It is an arithmetic number, because the mean of its divisors is an integer number (901446).

Almost surely, 2^21941580 is an apocalyptic number.

21941580 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 21941580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32452056).

21941580 is an abundant number, since it is smaller than the sum of its proper divisors (42962532).

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

21941580 is a wasteful number, since it uses less digits than its factorization.

21941580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063 (or 1042 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 21941580 is about 4684.1840271279. The cubic root of 21941580 is about 279.9556902673.

The spelling of 21941580 in words is "twenty-one million, nine hundred forty-one thousand, five hundred eighty".