172421478 has 24 divisors (see below), whose sum is σ = 389823408. Its totient is φ = 54974832.

The previous prime is 172421413. The next prime is 172421479. The reversal of 172421478 is 874124271.

172421478 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172421479) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 207825 + ... + 208652.

It is an arithmetic number, because the mean of its divisors is an integer number (16242642).

Almost surely, 2^172421478 is an apocalyptic number.

172421478 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

172421478 is an abundant number, since it is smaller than the sum of its proper divisors (217401930).

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

172421478 is a wasteful number, since it uses less digits than its factorization.

172421478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416508 (or 416505 counting only the distinct ones).

The product of its digits is 25088, while the sum is 36.

The square root of 172421478 is about 13130.9359148539. The cubic root of 172421478 is about 556.5836628285.

The spelling of 172421478 in words is "one hundred seventy-two million, four hundred twenty-one thousand, four hundred seventy-eight".