81246978 has 24 divisors (see below), whose sum is σ = 186390828. Its totient is φ = 25489152.

The previous prime is 81246967. The next prime is 81247031. The reversal of 81246978 is 87964218.

It can be written as a sum of positive squares in 2 ways, for example, as 71115489 + 10131489 = 8433^2 + 3183^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 132451 + ... + 133062.

Almost surely, 2^81246978 is an apocalyptic number.

81246978 is an abundant number, since it is smaller than the sum of its proper divisors (105143850).

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

81246978 is a wasteful number, since it uses less digits than its factorization.

81246978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265538 (or 265535 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 81246978 is about 9013.7105567019. The cubic root of 81246978 is about 433.1141828099.

The spelling of 81246978 in words is "eighty-one million, two hundred forty-six thousand, nine hundred seventy-eight".