673563978 has 32 divisors (see below), whose sum is σ = 1498029120. Its totient is φ = 224338320.

The previous prime is 673563977. The next prime is 673563991. The reversal of 673563978 is 879365376.

673563978 is a `hidden beast` number, since 6 + 7 + 3 + 563 + 9 + 78 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (673563971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72688 + ... + 81428.

It is an arithmetic number, because the mean of its divisors is an integer number (46813410).

Almost surely, 2^673563978 is an apocalyptic number.

673563978 is an abundant number, since it is smaller than the sum of its proper divisors (824465142).

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

673563978 is a wasteful number, since it uses less digits than its factorization.

673563978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10179 (or 10173 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 54.

The square root of 673563978 is about 25953.1111429825. Note that the first 4 decimals coincide. The cubic root of 673563978 is about 876.5828125751.

It can be divided in two parts, 673563 and 978, that added together give a triangular number (674541 = T₁₁₆₁).

The spelling of 673563978 in words is "six hundred seventy-three million, five hundred sixty-three thousand, nine hundred seventy-eight".