21970765 has 8 divisors (see below), whose sum is σ = 26475768. Its totient is φ = 17502720.

The previous prime is 21970763. The next prime is 21970771. The reversal of 21970765 is 56707912.

It can be written as a sum of positive squares in 4 ways, for example, as 5470921 + 16499844 = 2339^2 + 4062^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21970765 - 2¹ = 21970763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21970763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7912 + ... + 10321.

It is an arithmetic number, because the mean of its divisors is an integer number (3309471).

Almost surely, 2^21970765 is an apocalyptic number.

It is an amenable number.

21970765 is a deficient number, since it is larger than the sum of its proper divisors (4505003).

21970765 is a wasteful number, since it uses less digits than its factorization.

21970765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18479.

The product of its (nonzero) digits is 26460, while the sum is 37.

The square root of 21970765 is about 4687.2982623255. The cubic root of 21970765 is about 280.0797604407.

The spelling of 21970765 in words is "twenty-one million, nine hundred seventy thousand, seven hundred sixty-five".