81388498 has 4 divisors (see below), whose sum is σ = 122082750. Its totient is φ = 40694248.

The previous prime is 81388487. The next prime is 81388499. The reversal of 81388498 is 89488318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89488318 = 2 ⋅44744159.

It can be written as a sum of positive squares in only one way, i.e., 70610409 + 10778089 = 8403^2 + 3283^2 .

It is not an unprimeable number, because it can be changed into a prime (81388499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20347123 + ... + 20347126.

Almost surely, 2^81388498 is an apocalyptic number.

81388498 is a deficient number, since it is larger than the sum of its proper divisors (40694252).

81388498 is a wasteful number, since it uses less digits than its factorization.

81388498 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40694251.

The product of its digits is 442368, while the sum is 49.

The square root of 81388498 is about 9021.5574043510. The cubic root of 81388498 is about 433.3655101682.

The spelling of 81388498 in words is "eighty-one million, three hundred eighty-eight thousand, four hundred ninety-eight".