21362109509 has 16 divisors (see below), whose sum is σ = 24465031920. Its totient is φ = 18477849600.

The previous prime is 21362109497. The next prime is 21362109511. The reversal of 21362109509 is 90590126312.

It can be written as a sum of positive squares in 8 ways, for example, as 6009660484 + 15352449025 = 77522^2 + 123905^2 .

It is a cyclic number.

It is not a de Polignac number, because 21362109509 - 2¹⁶ = 21362043973 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 (21362105509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160442 + ... + 261659.

It is an arithmetic number, because the mean of its divisors is an integer number (1529064495).

Almost surely, 2^21362109509 is an apocalyptic number.

It is an amenable number.

21362109509 is a deficient number, since it is larger than the sum of its proper divisors (3102922411).

21362109509 is a wasteful number, since it uses less digits than its factorization.

21362109509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422360.

The product of its (nonzero) digits is 29160, while the sum is 38.

The spelling of 21362109509 in words is "twenty-one billion, three hundred sixty-two million, one hundred nine thousand, five hundred nine".