21077444 has 12 divisors (see below), whose sum is σ = 37785468. Its totient is φ = 10281600.

The previous prime is 21077431. The next prime is 21077447. The reversal of 21077444 is 44477012.

It can be written as a sum of positive squares in 2 ways, for example, as 5569600 + 15507844 = 2360^2 + 3938^2 .

It is not an unprimeable number, because it can be changed into a prime (21077447) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 64097 + ... + 64424.

It is an arithmetic number, because the mean of its divisors is an integer number (3148789).

Almost surely, 2^21077444 is an apocalyptic number.

It is an amenable number.

21077444 is a deficient number, since it is larger than the sum of its proper divisors (16708024).

21077444 is a wasteful number, since it uses less digits than its factorization.

21077444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128566 (or 128564 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 29.

The square root of 21077444 is about 4591.0177520894. The cubic root of 21077444 is about 276.2311478164.

The spelling of 21077444 in words is "twenty-one million, seventy-seven thousand, four hundred forty-four".