21165722701 has 8 divisors (see below), whose sum is σ = 21514456440. Its totient is φ = 20819453952.

The previous prime is 21165722689. The next prime is 21165722737. The reversal of 21165722701 is 10722756112.

It can be written as a sum of positive squares in 4 ways, for example, as 401200900 + 20764521801 = 20030^2 + 144099^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21165722701 - 2²⁷ = 21031504973 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 (21165722401) 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, 598930 + ... + 633283.

It is an arithmetic number, because the mean of its divisors is an integer number (2689307055).

Almost surely, 2^21165722701 is an apocalyptic number.

It is an amenable number.

21165722701 is a deficient number, since it is larger than the sum of its proper divisors (348733739).

21165722701 is a wasteful number, since it uses less digits than its factorization.

21165722701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1232495.

The product of its (nonzero) digits is 11760, while the sum is 34.

The spelling of 21165722701 in words is "twenty-one billion, one hundred sixty-five million, seven hundred twenty-two thousand, seven hundred one".