172947979 has 2 divisors, whose sum is σ = 172947980. Its totient is φ = 172947978.

The previous prime is 172947949. The next prime is 172947989. The reversal of 172947979 is 979749271.

It is a strong prime.

It is an emirp because it is prime and its reverse (979749271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 172947979 - 2⁵ = 172947947 is a prime.

It is a super-2 number, since 2×172947979² = 59822006880368882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (172947949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86473989 + 86473990.

It is an arithmetic number, because the mean of its divisors is an integer number (86473990).

Almost surely, 2^172947979 is an apocalyptic number.

172947979 is a deficient number, since it is larger than the sum of its proper divisors (1).

172947979 is an equidigital number, since it uses as much as digits as its factorization.

172947979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2000376, while the sum is 55.

The square root of 172947979 is about 13150.9687475866. The cubic root of 172947979 is about 557.1496095015.

The spelling of 172947979 in words is "one hundred seventy-two million, nine hundred forty-seven thousand, nine hundred seventy-nine".