81651892 has 48 divisors (see below), whose sum is σ = 177479680. Its totient is φ = 32076000.

The previous prime is 81651841. The next prime is 81651943. The reversal of 81651892 is 29815618.

It is an interprime number because it is at equal distance from previous prime (81651841) and next prime (81651943).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14017 + ... + 18967.

Almost surely, 2^81651892 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81651892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88739840).

81651892 is an abundant number, since it is smaller than the sum of its proper divisors (95827788).

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

81651892 is a wasteful number, since it uses less digits than its factorization.

81651892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5012 (or 5010 counting only the distinct ones).

The product of its digits is 34560, while the sum is 40.

The square root of 81651892 is about 9036.1436464899. The cubic root of 81651892 is about 433.8325006473.

The spelling of 81651892 in words is "eighty-one million, six hundred fifty-one thousand, eight hundred ninety-two".