18421661958 has 64 divisors (see below), whose sum is σ = 44606661120. Its totient is φ = 4951153152.

The previous prime is 18421661939. The next prime is 18421661959. The reversal of 18421661958 is 85916612481.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 18421661958.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421661959) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1660233 + ... + 1671291.

It is an arithmetic number, because the mean of its divisors is an integer number (696979080).

Almost surely, 2^18421661958 is an apocalyptic number.

18421661958 is an abundant number, since it is smaller than the sum of its proper divisors (26184999162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18421661958 is a wasteful number, since it uses less digits than its factorization.

18421661958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13421.

The product of its digits is 829440, while the sum is 51.

The spelling of 18421661958 in words is "eighteen billion, four hundred twenty-one million, six hundred sixty-one thousand, nine hundred fifty-eight".