21725580 has 24 divisors (see below), whose sum is σ = 60831792. Its totient is φ = 5793472.

The previous prime is 21725579. The next prime is 21725581. The reversal of 21725580 is 8552712.

It is an interprime number because it is at equal distance from previous prime (21725579) and next prime (21725581).

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 (21725581) 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, 180987 + ... + 181106.

It is an arithmetic number, because the mean of its divisors is an integer number (2534658).

Almost surely, 2^21725580 is an apocalyptic number.

21725580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21725580 is an abundant number, since it is smaller than the sum of its proper divisors (39106212).

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

21725580 is a wasteful number, since it uses less digits than its factorization.

21725580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362105 (or 362103 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 21725580 is about 4661.0706924482. The cubic root of 21725580 is about 279.0340010720.

The spelling of 21725580 in words is "twenty-one million, seven hundred twenty-five thousand, five hundred eighty".