81774401440 has 48 divisors (see below), whose sum is σ = 195838517448. Its totient is φ = 32261677056.

The previous prime is 81774401437. The next prime is 81774401441. The reversal of 81774401440 is 4410447718.

It can be written as a sum of positive squares in 4 ways, for example, as 79463099664 + 2311301776 = 281892^2 + 48076^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 81774401393 and 81774401402.

It is not an unprimeable number, because it can be changed into a prime (81774401441) 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, 3488937 + ... + 3512296.

Almost surely, 2^81774401440 is an apocalyptic number.

81774401440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81774401440 is an abundant number, since it is smaller than the sum of its proper divisors (114064116008).

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

81774401440 is a wasteful number, since it uses less digits than its factorization.

81774401440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7001321 (or 7001313 counting only the distinct ones).

The product of its (nonzero) digits is 100352, while the sum is 40.

The spelling of 81774401440 in words is "eighty-one billion, seven hundred seventy-four million, four hundred one thousand, four hundred forty".