21481900509 has 16 divisors (see below), whose sum is σ = 29052777600. Its totient is φ = 14116240320.

The previous prime is 21481900507. The next prime is 21481900537. The reversal of 21481900509 is 90500918412.

It is not a de Polignac number, because 21481900509 - 2¹ = 21481900507 is a prime.

It is a super-2 number, since 2×21481900509² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481900507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1174567 + ... + 1192715.

It is an arithmetic number, because the mean of its divisors is an integer number (1815798600).

Almost surely, 2^21481900509 is an apocalyptic number.

It is an amenable number.

21481900509 is a deficient number, since it is larger than the sum of its proper divisors (7570877091).

21481900509 is a wasteful number, since it uses less digits than its factorization.

21481900509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23780.

The product of its (nonzero) digits is 25920, while the sum is 39.

The spelling of 21481900509 in words is "twenty-one billion, four hundred eighty-one million, nine hundred thousand, five hundred nine".