161878457 has 8 divisors (see below), whose sum is σ = 176058120. Its totient is φ = 147945600.

The previous prime is 161878447. The next prime is 161878459. The reversal of 161878457 is 754878161.

It can be written as a sum of positive squares in 4 ways, for example, as 13623481 + 148254976 = 3691^2 + 12176^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161878457 - 2¹⁰ = 161877433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161878459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60332 + ... + 62957.

It is an arithmetic number, because the mean of its divisors is an integer number (22007265).

Almost surely, 2^161878457 is an apocalyptic number.

It is an amenable number.

161878457 is a deficient number, since it is larger than the sum of its proper divisors (14179663).

161878457 is a wasteful number, since it uses less digits than its factorization.

161878457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123403.

The product of its digits is 376320, while the sum is 47.

The square root of 161878457 is about 12723.1465054836. The cubic root of 161878457 is about 544.9998114636. Note that the first 3 decimals are identical.

The spelling of 161878457 in words is "one hundred sixty-one million, eight hundred seventy-eight thousand, four hundred fifty-seven".