81492487 has 4 divisors (see below), whose sum is σ = 81573480. Its totient is φ = 81411496.

The previous prime is 81492469. The next prime is 81492491. The reversal of 81492487 is 78429418.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81492487 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 (81492457) 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, 38968 + ... + 41005.

It is an arithmetic number, because the mean of its divisors is an integer number (20393370).

Almost surely, 2^81492487 is an apocalyptic number.

81492487 is a deficient number, since it is larger than the sum of its proper divisors (80993).

81492487 is a wasteful number, since it uses less digits than its factorization.

81492487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80992.

The product of its digits is 129024, while the sum is 43.

The square root of 81492487 is about 9027.3189264587. The cubic root of 81492487 is about 433.5500000641.

The spelling of 81492487 in words is "eighty-one million, four hundred ninety-two thousand, four hundred eighty-seven".