81351996 has 96 divisors (see below), whose sum is σ = 220416000. Its totient is φ = 23094720.

The previous prime is 81351983. The next prime is 81351997. The reversal of 81351996 is 69915318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81351997) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 408705 + ... + 408903.

It is an arithmetic number, because the mean of its divisors is an integer number (2296000).

Almost surely, 2^81351996 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 81351996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110208000).

81351996 is an abundant number, since it is smaller than the sum of its proper divisors (139064004).

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

81351996 is a wasteful number, since it uses less digits than its factorization.

81351996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399 (or 397 counting only the distinct ones).

The product of its digits is 58320, while the sum is 42.

The square root of 81351996 is about 9019.5341343109. The cubic root of 81351996 is about 433.3007136524.

The spelling of 81351996 in words is "eighty-one million, three hundred fifty-one thousand, nine hundred ninety-six".