81790464 has 80 divisors (see below), whose sum is σ = 249055488. Its totient is φ = 23365632.

The previous prime is 81790463. The next prime is 81790477. The reversal of 81790464 is 46409718.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81790463) 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, 6949 + ... + 14555.

Almost surely, 2^81790464 is an apocalyptic number.

81790464 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81790464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124527744).

81790464 is an abundant number, since it is smaller than the sum of its proper divisors (167265024).

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

81790464 is an equidigital number, since it uses as much as digits as its factorization.

81790464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7635 (or 7619 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 81790464 is about 9043.8080474986. The cubic root of 81790464 is about 434.0777820057.

The spelling of 81790464 in words is "eighty-one million, seven hundred ninety thousand, four hundred sixty-four".