18615241981 has 16 divisors (see below), whose sum is σ = 22212543744. Its totient is φ = 15253248384.

The previous prime is 18615241979. The next prime is 18615242069. The reversal of 18615241981 is 18914251681.

It is a cyclic number.

It is not a de Polignac number, because 18615241981 - 2¹ = 18615241979 is a prime.

It is a super-2 number, since 2×18615241981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18615241921) 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, 249255 + ... + 315211.

It is an arithmetic number, because the mean of its divisors is an integer number (1388283984).

Almost surely, 2^18615241981 is an apocalyptic number.

It is an amenable number.

18615241981 is a deficient number, since it is larger than the sum of its proper divisors (3597301763).

18615241981 is a wasteful number, since it uses less digits than its factorization.

18615241981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67740.

The product of its digits is 138240, while the sum is 46.

The spelling of 18615241981 in words is "eighteen billion, six hundred fifteen million, two hundred forty-one thousand, nine hundred eighty-one".