81980359 has 4 divisors (see below), whose sum is σ = 82247704. Its totient is φ = 81713016.

The previous prime is 81980333. The next prime is 81980377. The reversal of 81980359 is 95308918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81980359 - 2¹³ = 81972167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81980309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133212 + ... + 133825.

It is an arithmetic number, because the mean of its divisors is an integer number (20561926).

Almost surely, 2^81980359 is an apocalyptic number.

81980359 is a deficient number, since it is larger than the sum of its proper divisors (267345).

81980359 is a wasteful number, since it uses less digits than its factorization.

81980359 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267344.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 81980359 is about 9054.3005803872. The cubic root of 81980359 is about 434.4134588311.

The spelling of 81980359 in words is "eighty-one million, nine hundred eighty thousand, three hundred fifty-nine".