18920172405 has 48 divisors (see below), whose sum is σ = 31126114944. Its totient is φ = 9810028800.

The previous prime is 18920172377. The next prime is 18920172409. The reversal of 18920172405 is 50427102981.

It is not a de Polignac number, because 18920172405 - 2¹⁶ = 18920106869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18920172409) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 47657667 + ... + 47658063.

It is an arithmetic number, because the mean of its divisors is an integer number (648460728).

Almost surely, 2^18920172405 is an apocalyptic number.

18920172405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18920172405 is a deficient number, since it is larger than the sum of its proper divisors (12205942539).

18920172405 is an equidigital number, since it uses as much as digits as its factorization.

18920172405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1006 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 39.

The spelling of 18920172405 in words is "eighteen billion, nine hundred twenty million, one hundred seventy-two thousand, four hundred five".