81273550 has 12 divisors (see below), whose sum is σ = 151168896. Its totient is φ = 32509400.

The previous prime is 81273547. The next prime is 81273553. The reversal of 81273550 is 5537218.

It is an interprime number because it is at equal distance from previous prime (81273547) and next prime (81273553).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81273553) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 812686 + ... + 812785.

It is an arithmetic number, because the mean of its divisors is an integer number (12597408).

Almost surely, 2^81273550 is an apocalyptic number.

81273550 is a deficient number, since it is larger than the sum of its proper divisors (69895346).

81273550 is a wasteful number, since it uses less digits than its factorization.

81273550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1625483 (or 1625478 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 81273550 is about 9015.1844129779. The cubic root of 81273550 is about 433.1613946403.

The spelling of 81273550 in words is "eighty-one million, two hundred seventy-three thousand, five hundred fifty".