21700445 has 24 divisors (see below), whose sum is σ = 28728072. Its totient is φ = 15724800.

The previous prime is 21700409. The next prime is 21700493. The reversal of 21700445 is 54400712.

21700445 = 271² + 272² + ... + 439².

It can be written as a sum of positive squares in 12 ways, for example, as 21631801 + 68644 = 4651^2 + 262^2 .

It is not a de Polignac number, because 21700445 - 2¹² = 21696349 is a prime.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21700445.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51335 + ... + 51755.

It is an arithmetic number, because the mean of its divisors is an integer number (1197003).

Almost surely, 2^21700445 is an apocalyptic number.

It is an amenable number.

21700445 is a deficient number, since it is larger than the sum of its proper divisors (7027627).

21700445 is a wasteful number, since it uses less digits than its factorization.

21700445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21700445 is about 4658.3736432364. The cubic root of 21700445 is about 278.9263518389.

The spelling of 21700445 in words is "twenty-one million, seven hundred thousand, four hundred forty-five".