21607444 has 6 divisors (see below), whose sum is σ = 37813034. Its totient is φ = 10803720.

The previous prime is 21607441. The next prime is 21607447. The reversal of 21607444 is 44470612.

It is an interprime number because it is at equal distance from previous prime (21607441) and next prime (21607447).

It can be written as a sum of positive squares in only one way, i.e., 16499844 + 5107600 = 4062^2 + 2260^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21607441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2700927 + ... + 2700934.

Almost surely, 2^21607444 is an apocalyptic number.

It is an amenable number.

21607444 is a deficient number, since it is larger than the sum of its proper divisors (16205590).

21607444 is a wasteful number, since it uses less digits than its factorization.

21607444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401865 (or 5401863 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 28.

The square root of 21607444 is about 4648.3807933516. The cubic root of 21607444 is about 278.5273189231.

It can be divided in two parts, 2160 and 7444, that added together give a square (9604 = 98²).

The spelling of 21607444 in words is "twenty-one million, six hundred seven thousand, four hundred forty-four".