21518995461 has 16 divisors (see below), whose sum is σ = 29143635840. Its totient is φ = 14121819200.

The previous prime is 21518995439. The next prime is 21518995549. The reversal of 21518995461 is 16459981512.

It is a cyclic number.

It is not a de Polignac number, because 21518995461 - 2⁵ = 21518995429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518990461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152841 + ... + 257678.

It is an arithmetic number, because the mean of its divisors is an integer number (1821477240).

Almost surely, 2^21518995461 is an apocalyptic number.

It is an amenable number.

21518995461 is a deficient number, since it is larger than the sum of its proper divisors (7624640379).

21518995461 is a wasteful number, since it uses less digits than its factorization.

21518995461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410796.

The product of its digits is 777600, while the sum is 51.

The spelling of 21518995461 in words is "twenty-one billion, five hundred eighteen million, nine hundred ninety-five thousand, four hundred sixty-one".