21577140 has 72 divisors (see below), whose sum is σ = 70492968. Its totient is φ = 5310720.

The previous prime is 21577133. The next prime is 21577163. The reversal of 21577140 is 4177512.

It can be written as a sum of positive squares in 4 ways, for example, as 2862864 + 18714276 = 1692^2 + 4326^2 .

It is a congruent number.

It is an unprimeable number.

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, 2271 + ... + 6950.

It is an arithmetic number, because the mean of its divisors is an integer number (979069).

Almost surely, 2^21577140 is an apocalyptic number.

21577140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21577140 is an abundant number, since it is smaller than the sum of its proper divisors (48915828).

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

21577140 is a wasteful number, since it uses less digits than its factorization.

21577140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9249 (or 9244 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21577140 is about 4645.1200199780. The cubic root of 21577140 is about 278.3970483734.

The spelling of 21577140 in words is "twenty-one million, five hundred seventy-seven thousand, one hundred forty".