81410640 has 40 divisors (see below), whose sum is σ = 252373728. Its totient is φ = 21709440.

The previous prime is 81410621. The next prime is 81410647. The reversal of 81410640 is 4601418.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 81410640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81410647) 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, 169366 + ... + 169845.

Almost surely, 2^81410640 is an apocalyptic number.

81410640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81410640 is an abundant number, since it is smaller than the sum of its proper divisors (170963088).

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

81410640 is a wasteful number, since it uses less digits than its factorization.

81410640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339227 (or 339221 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 81410640 is about 9022.7844926054. The cubic root of 81410640 is about 433.4048060938.

The spelling of 81410640 in words is "eighty-one million, four hundred ten thousand, six hundred forty".