81902730 has 128 divisors (see below), whose sum is σ = 254822400. Its totient is φ = 16360704.

The previous prime is 81902729. The next prime is 81902731. The reversal of 81902730 is 3720918.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81902729) and next prime (81902731).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81902731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 51081 + ... + 52659.

It is an arithmetic number, because the mean of its divisors is an integer number (1990800).

Almost surely, 2^81902730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81902730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127411200).

81902730 is an abundant number, since it is smaller than the sum of its proper divisors (172919670).

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

81902730 is a wasteful number, since it uses less digits than its factorization.

81902730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1628.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 81902730 is about 9050.0127071734. The cubic root of 81902730 is about 434.2762969841.

The spelling of 81902730 in words is "eighty-one million, nine hundred two thousand, seven hundred thirty".