21382757 has 12 divisors (see below), whose sum is σ = 23896908. Its totient is φ = 19113600.

The previous prime is 21382747. The next prime is 21382759. The reversal of 21382757 is 75728312.

It can be written as a sum of positive squares in 2 ways, for example, as 1437601 + 19945156 = 1199^2 + 4466^2 .

It is not a de Polignac number, because 21382757 - 2⁴ = 21382741 is a prime.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382759) 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 11 ways as a sum of consecutive naturals, for example, 5933 + ... + 8829.

It is an arithmetic number, because the mean of its divisors is an integer number (1991409).

Almost surely, 2^21382757 is an apocalyptic number.

It is an amenable number.

21382757 is a deficient number, since it is larger than the sum of its proper divisors (2514151).

21382757 is a wasteful number, since it uses less digits than its factorization.

21382757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2980 (or 2969 counting only the distinct ones).

The product of its digits is 23520, while the sum is 35.

The square root of 21382757 is about 4624.1493271736. The cubic root of 21382757 is about 277.5585224082.

The spelling of 21382757 in words is "twenty-one million, three hundred eighty-two thousand, seven hundred fifty-seven".