81249983 has 4 divisors (see below), whose sum is σ = 81275688. Its totient is φ = 81224280.

The previous prime is 81249979. The next prime is 81249997. The reversal of 81249983 is 38994218.

It is a happy number.

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 81249983 - 2² = 81249979 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 (81249913) 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, 7316 + ... + 14697.

It is an arithmetic number, because the mean of its divisors is an integer number (20318922).

Almost surely, 2^81249983 is an apocalyptic number.

81249983 is a deficient number, since it is larger than the sum of its proper divisors (25705).

81249983 is a wasteful number, since it uses less digits than its factorization.

81249983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25704.

The product of its digits is 124416, while the sum is 44.

The square root of 81249983 is about 9013.8772456696. The cubic root of 81249983 is about 433.1195224631.

The spelling of 81249983 in words is "eighty-one million, two hundred forty-nine thousand, nine hundred eighty-three".