21145542999 has 16 divisors (see below), whose sum is σ = 32240279808. Its totient is φ = 12076229952.

The previous prime is 21145542961. The next prime is 21145543087. The reversal of 21145542999 is 99924554112.

It is not a de Polignac number, because 21145542999 - 2¹⁷ = 21145411927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145542949) 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, 251502 + ... + 324875.

It is an arithmetic number, because the mean of its divisors is an integer number (2015017488).

Almost surely, 2^21145542999 is an apocalyptic number.

21145542999 is a deficient number, since it is larger than the sum of its proper divisors (11094736809).

21145542999 is a wasteful number, since it uses less digits than its factorization.

21145542999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578134.

The product of its digits is 1166400, while the sum is 51.

The spelling of 21145542999 in words is "twenty-one billion, one hundred forty-five million, five hundred forty-two thousand, nine hundred ninety-nine".