661074978 has 16 divisors (see below), whose sum is σ = 1322690976. Its totient is φ = 220268160.

The previous prime is 661074977. The next prime is 661074979. The reversal of 661074978 is 879470166.

It is an interprime number because it is at equal distance from previous prime (661074977) and next prime (661074979).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (661074977) 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, 5688 + ... + 36803.

It is an arithmetic number, because the mean of its divisors is an integer number (82668186).

Almost surely, 2^661074978 is an apocalyptic number.

661074978 is an abundant number, since it is smaller than the sum of its proper divisors (661615998).

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

661074978 is a wasteful number, since it uses less digits than its factorization.

661074978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45089.

The product of its (nonzero) digits is 508032, while the sum is 48.

The square root of 661074978 is about 25711.3783761198. The cubic root of 661074978 is about 871.1312091897.

The spelling of 661074978 in words is "six hundred sixty-one million, seventy-four thousand, nine hundred seventy-eight".