81742730 has 16 divisors (see below), whose sum is σ = 149631840. Its totient is φ = 32142672.

The previous prime is 81742723. The next prime is 81742733. The reversal of 81742730 is 3724718.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81742733) 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, 68684 + ... + 69863.

It is an arithmetic number, because the mean of its divisors is an integer number (9351990).

Almost surely, 2^81742730 is an apocalyptic number.

81742730 is a deficient number, since it is larger than the sum of its proper divisors (67889110).

81742730 is a wasteful number, since it uses less digits than its factorization.

81742730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138613.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 81742730 is about 9041.1686191554. The cubic root of 81742730 is about 433.9933210550.

It can be divided in two parts, 8 and 1742730, that multiplied together give a triangular number (13941840 = T₅₂₈₀).

The spelling of 81742730 in words is "eighty-one million, seven hundred forty-two thousand, seven hundred thirty".