7661978 has 16 divisors (see below), whose sum is σ = 12181920. Its totient is φ = 3604176.

The previous prime is 7661963. The next prime is 7661981. The reversal of 7661978 is 8791667.

It is an unprimeable number.

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, 5576 + ... + 6812.

It is an arithmetic number, because the mean of its divisors is an integer number (761370).

Almost surely, 2^7661978 is an apocalyptic number.

7661978 is a deficient number, since it is larger than the sum of its proper divisors (4519942).

7661978 is a wasteful number, since it uses less digits than its factorization.

7661978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1421.

The product of its digits is 127008, while the sum is 44.

The square root of 7661978 is about 2768.0278177793. The cubic root of 7661978 is about 197.1425184279.

It can be divided in two parts, 766 and 1978, that added together give a cube (2744 = 14³).

The spelling of 7661978 in words is "seven million, six hundred sixty-one thousand, nine hundred seventy-eight".