172479781 has 2 divisors, whose sum is σ = 172479782. Its totient is φ = 172479780.

The previous prime is 172479761. The next prime is 172479809. The reversal of 172479781 is 187974271.

172479781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125776225 + 46703556 = 11215^2 + 6834^2 .

It is a cyclic number.

It is not a de Polignac number, because 172479781 - 2⁷ = 172479653 is a prime.

It is a super-2 number, since 2×172479781² = 59498549707615922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172479731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86239890 + 86239891.

It is an arithmetic number, because the mean of its divisors is an integer number (86239891).

Almost surely, 2^172479781 is an apocalyptic number.

It is an amenable number.

172479781 is a deficient number, since it is larger than the sum of its proper divisors (1).

172479781 is an equidigital number, since it uses as much as digits as its factorization.

172479781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 197568, while the sum is 46.

The square root of 172479781 is about 13133.1557898321. The cubic root of 172479781 is about 556.6463905906.

It can be divided in two parts, 17247 and 9781, that added together give a triangular number (27028 = T₂₃₂).

The spelling of 172479781 in words is "one hundred seventy-two million, four hundred seventy-nine thousand, seven hundred eighty-one".