21235690309 has 16 divisors (see below), whose sum is σ = 23867712000. Its totient is φ = 18795789936.

The previous prime is 21235690303. The next prime is 21235690337. The reversal of 21235690309 is 90309653212.

It is a cyclic number.

It is not a de Polignac number, because 21235690309 - 2⁷ = 21235690181 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 (21235690303) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 546259 + ... + 583840.

It is an arithmetic number, because the mean of its divisors is an integer number (1491732000).

Almost surely, 2^21235690309 is an apocalyptic number.

It is an amenable number.

21235690309 is a deficient number, since it is larger than the sum of its proper divisors (2632021691).

21235690309 is a wasteful number, since it uses less digits than its factorization.

21235690309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1130184.

The product of its (nonzero) digits is 87480, while the sum is 40.

The spelling of 21235690309 in words is "twenty-one billion, two hundred thirty-five million, six hundred ninety thousand, three hundred nine".