172206978 has 16 divisors (see below), whose sum is σ = 344739456. Its totient is φ = 57348080.

The previous prime is 172206973. The next prime is 172207019. The reversal of 172206978 is 879602271.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (172206973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6393 + ... + 19628.

It is an arithmetic number, because the mean of its divisors is an integer number (21546216).

Almost surely, 2^172206978 is an apocalyptic number.

172206978 is an abundant number, since it is smaller than the sum of its proper divisors (172532478).

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

172206978 is a wasteful number, since it uses less digits than its factorization.

172206978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27129.

The product of its (nonzero) digits is 84672, while the sum is 42.

The square root of 172206978 is about 13122.7656383858. The cubic root of 172206978 is about 556.3527620943.

The spelling of 172206978 in words is "one hundred seventy-two million, two hundred six thousand, nine hundred seventy-eight".