21970044 has 18 divisors (see below), whose sum is σ = 55535480. Its totient is φ = 7323336.

The previous prime is 21970043. The next prime is 21970051. The reversal of 21970044 is 44007912.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21970043) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 305104 + ... + 305175.

Almost surely, 2^21970044 is an apocalyptic number.

It is an amenable number.

21970044 is an abundant number, since it is smaller than the sum of its proper divisors (33565436).

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

21970044 is a wasteful number, since it uses less digits than its factorization.

21970044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610289 (or 610284 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21970044 is about 4687.2213517179. The cubic root of 21970044 is about 280.0766966767.

Adding to 21970044 its reverse (44007912), we get a palindrome (65977956).

The spelling of 21970044 in words is "twenty-one million, nine hundred seventy thousand, forty-four".