21577868 has 12 divisors (see below), whose sum is σ = 40666080. Its totient is φ = 9958992.

The previous prime is 21577861. The next prime is 21577877. The reversal of 21577868 is 86877512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21577861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207428 + ... + 207531.

It is an arithmetic number, because the mean of its divisors is an integer number (3388840).

Almost surely, 2^21577868 is an apocalyptic number.

It is an amenable number.

21577868 is a deficient number, since it is larger than the sum of its proper divisors (19088212).

21577868 is a wasteful number, since it uses less digits than its factorization.

21577868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414976 (or 414974 counting only the distinct ones).

The product of its digits is 188160, while the sum is 44.

The square root of 21577868 is about 4645.1983811243. The cubic root of 21577868 is about 278.4001793223.

The spelling of 21577868 in words is "twenty-one million, five hundred seventy-seven thousand, eight hundred sixty-eight".