81953492 has 6 divisors (see below), whose sum is σ = 143418618. Its totient is φ = 40976744.

The previous prime is 81953471. The next prime is 81953513. The reversal of 81953492 is 29435918.

It is an interprime number because it is at equal distance from previous prime (81953471) and next prime (81953513).

It can be written as a sum of positive squares in only one way, i.e., 78251716 + 3701776 = 8846^2 + 1924^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10244183 + ... + 10244190.

It is an arithmetic number, because the mean of its divisors is an integer number (23903103).

Almost surely, 2^81953492 is an apocalyptic number.

It is an amenable number.

81953492 is a deficient number, since it is larger than the sum of its proper divisors (61465126).

81953492 is a wasteful number, since it uses less digits than its factorization.

81953492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20488377 (or 20488375 counting only the distinct ones).

The product of its digits is 77760, while the sum is 41.

The square root of 81953492 is about 9052.8167992068. The cubic root of 81953492 is about 434.3659976189.

The spelling of 81953492 in words is "eighty-one million, nine hundred fifty-three thousand, four hundred ninety-two".