172781421 has 32 divisors (see below), whose sum is σ = 263088000. Its totient is φ = 100177920.

The previous prime is 172781393. The next prime is 172781429. The reversal of 172781421 is 124187271.

It is not a de Polignac number, because 172781421 - 2¹³ = 172773229 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172781429) 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, 37555 + ... + 41903.

It is an arithmetic number, because the mean of its divisors is an integer number (8221500).

Almost surely, 2^172781421 is an apocalyptic number.

It is an amenable number.

172781421 is a deficient number, since it is larger than the sum of its proper divisors (90306579).

172781421 is a wasteful number, since it uses less digits than its factorization.

172781421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4429.

The product of its digits is 6272, while the sum is 33.

The square root of 172781421 is about 13144.6346849199. The cubic root of 172781421 is about 556.9706972628.

The spelling of 172781421 in words is "one hundred seventy-two million, seven hundred eighty-one thousand, four hundred twenty-one".