21077388 has 24 divisors (see below), whose sum is σ = 54645360. Its totient is φ = 7025760.

The previous prime is 21077369. The next prime is 21077393. The reversal of 21077388 is 88377012.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 7 ways as a sum of consecutive naturals, for example, 97473 + ... + 97688.

It is an arithmetic number, because the mean of its divisors is an integer number (2276890).

Almost surely, 2^21077388 is an apocalyptic number.

It is an amenable number.

21077388 is an abundant number, since it is smaller than the sum of its proper divisors (33567972).

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

21077388 is a wasteful number, since it uses less digits than its factorization.

21077388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195174 (or 195166 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 21077388 is about 4591.0116532198. The cubic root of 21077388 is about 276.2309031795.

The spelling of 21077388 in words is "twenty-one million, seventy-seven thousand, three hundred eighty-eight".