81553878 has 40 divisors (see below), whose sum is σ = 208849872. Its totient is φ = 23300784.

The previous prime is 81553877. The next prime is 81553907. The reversal of 81553878 is 87835518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81553873) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 34825 + ... + 37092.

Almost surely, 2^81553878 is an apocalyptic number.

81553878 is an abundant number, since it is smaller than the sum of its proper divisors (127295994).

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

81553878 is a wasteful number, since it uses less digits than its factorization.

81553878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71938 (or 71929 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 81553878 is about 9030.7185760603. The cubic root of 81553878 is about 433.6588419473.

The spelling of 81553878 in words is "eighty-one million, five hundred fifty-three thousand, eight hundred seventy-eight".