81491478 has 16 divisors (see below), whose sum is σ = 164022960. Its totient is φ = 26990496.

The previous prime is 81491471. The next prime is 81491483. The reversal of 81491478 is 87419418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81491471) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42313 + ... + 44196.

It is an arithmetic number, because the mean of its divisors is an integer number (10251435).

Almost surely, 2^81491478 is an apocalyptic number.

81491478 is an abundant number, since it is smaller than the sum of its proper divisors (82531482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81491478 is a wasteful number, since it uses less digits than its factorization.

81491478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86671.

The product of its digits is 64512, while the sum is 42.

The square root of 81491478 is about 9027.2630403683. The cubic root of 81491478 is about 433.5482107222.

The spelling of 81491478 in words is "eighty-one million, four hundred ninety-one thousand, four hundred seventy-eight".