81977370 has 16 divisors (see below), whose sum is σ = 196745760. Its totient is φ = 21860624.

The previous prime is 81977369. The next prime is 81977377. The reversal of 81977370 is 7377918.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81977377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1366260 + ... + 1366319.

It is an arithmetic number, because the mean of its divisors is an integer number (12296610).

Almost surely, 2^81977370 is an apocalyptic number.

81977370 is an abundant number, since it is smaller than the sum of its proper divisors (114768390).

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

81977370 is a wasteful number, since it uses less digits than its factorization.

81977370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2732589.

The product of its (nonzero) digits is 74088, while the sum is 42.

The square root of 81977370 is about 9054.1355191978. The cubic root of 81977370 is about 434.4081792022.

The spelling of 81977370 in words is "eighty-one million, nine hundred seventy-seven thousand, three hundred seventy".