21090229901 has 4 divisors (see below), whose sum is σ = 22712555292. Its totient is φ = 19467904512.

The previous prime is 21090229889. The next prime is 21090229921. The reversal of 21090229901 is 10992209012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4140793801 + 16949436100 = 64349^2 + 130190^2 .

It is a cyclic number.

It is not a de Polignac number, because 21090229901 - 2²⁶ = 21023121037 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 (21090229921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 811162676 + ... + 811162701.

It is an arithmetic number, because the mean of its divisors is an integer number (5678138823).

Almost surely, 2^21090229901 is an apocalyptic number.

It is an amenable number.

21090229901 is a deficient number, since it is larger than the sum of its proper divisors (1622325391).

21090229901 is a wasteful number, since it uses less digits than its factorization.

21090229901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1622325390.

The product of its (nonzero) digits is 5832, while the sum is 35.

The spelling of 21090229901 in words is "twenty-one billion, ninety million, two hundred twenty-nine thousand, nine hundred one".