81978963 has 16 divisors (see below), whose sum is σ = 120009216. Its totient is φ = 49364640.

The previous prime is 81978929. The next prime is 81978983. The reversal of 81978963 is 36987918.

It is not a de Polignac number, because 81978963 - 2⁶ = 81978899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81978983) 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, 2731 + ... + 13092.

It is an arithmetic number, because the mean of its divisors is an integer number (7500576).

Almost surely, 2^81978963 is an apocalyptic number.

81978963 is a deficient number, since it is larger than the sum of its proper divisors (38030253).

81978963 is a wasteful number, since it uses less digits than its factorization.

81978963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15994.

The product of its digits is 653184, while the sum is 51.

The square root of 81978963 is about 9054.2234896207. The cubic root of 81978963 is about 434.4109930184.

The spelling of 81978963 in words is "eighty-one million, nine hundred seventy-eight thousand, nine hundred sixty-three".