18991377450 has 120 divisors (see below), whose sum is σ = 55872090252. Its totient is φ = 4766446080.

The previous prime is 18991377437. The next prime is 18991377473. The reversal of 18991377450 is 5477319981.

It is a happy number.

18991377450 is a `hidden beast` number, since 189 + 9 + 1 + 3 + 7 + 7 + 450 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 5071861089 + 13919516361 = 71217^2 + 117981^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 69069 + ... + 206768.

Almost surely, 2^18991377450 is an apocalyptic number.

18991377450 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18991377450 is an abundant number, since it is smaller than the sum of its proper divisors (36880712802).

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

18991377450 is a wasteful number, since it uses less digits than its factorization.

18991377450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275878 (or 275864 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 54.

The spelling of 18991377450 in words is "eighteen billion, nine hundred ninety-one million, three hundred seventy-seven thousand, four hundred fifty".