21085461899 has 12 divisors (see below), whose sum is σ = 22284407376. Its totient is φ = 19913267088.

The previous prime is 21085461871. The next prime is 21085461953. The reversal of 21085461899 is 99816458012.

It is not a de Polignac number, because 21085461899 - 2¹⁶ = 21085396363 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21085461899.

It is not an unprimeable number, because it can be changed into a prime (21085461499) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70097 + ... + 216989.

It is an arithmetic number, because the mean of its divisors is an integer number (1857033948).

Almost surely, 2^21085461899 is an apocalyptic number.

21085461899 is a deficient number, since it is larger than the sum of its proper divisors (1198945477).

21085461899 is an equidigital number, since it uses as much as digits as its factorization.

21085461899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147074 (or 146995 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 53.

The spelling of 21085461899 in words is "twenty-one billion, eighty-five million, four hundred sixty-one thousand, eight hundred ninety-nine".