81898992400 has 135 divisors (see below), whose sum is σ = 202257992253. Its totient is φ = 31869004800.

The previous prime is 81898992367. The next prime is 81898992421. The reversal of 81898992400 is 429989818.

The square root of 81898992400 is 286180.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 73651446544 + 8247545856 = 271388^2 + 90816^2 .

It is a super-2 number, since 2×81898992400² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 234667426 + ... + 234667774.

Almost surely, 2^81898992400 is an apocalyptic number.

81898992400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

81898992400 is the 286180-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81898992400

81898992400 is an abundant number, since it is smaller than the sum of its proper divisors (120358999853).

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

81898992400 is an equidigital number, since it uses as much as digits as its factorization.

81898992400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798 (or 397 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 58.

The spelling of 81898992400 in words is "eighty-one billion, eight hundred ninety-eight million, nine hundred ninety-two thousand, four hundred".