81442949 has 16 divisors (see below), whose sum is σ = 99984000. Its totient is φ = 66128832.

The previous prime is 81442919. The next prime is 81442967. The reversal of 81442949 is 94924418.

It is not a de Polignac number, because 81442949 - 2²⁰ = 80394373 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 (81442909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 269 + ... + 12765.

It is an arithmetic number, because the mean of its divisors is an integer number (6249000).

Almost surely, 2^81442949 is an apocalyptic number.

It is an amenable number.

81442949 is a deficient number, since it is larger than the sum of its proper divisors (18541051).

81442949 is a wasteful number, since it uses less digits than its factorization.

81442949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12537 (or 12523 counting only the distinct ones).

The product of its digits is 82944, while the sum is 41.

The square root of 81442949 is about 9024.5747268223. The cubic root of 81442949 is about 433.4621328506.

The spelling of 81442949 in words is "eighty-one million, four hundred forty-two thousand, nine hundred forty-nine".