81451650 has 48 divisors (see below), whose sum is σ = 230860224. Its totient is φ = 18617280.

The previous prime is 81451631. The next prime is 81451681. The reversal of 81451650 is 5615418.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37737 + ... + 39836.

It is an arithmetic number, because the mean of its divisors is an integer number (4809588).

Almost surely, 2^81451650 is an apocalyptic number.

81451650 is an abundant number, since it is smaller than the sum of its proper divisors (149408574).

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

81451650 is a wasteful number, since it uses less digits than its factorization.

81451650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77595 (or 77590 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 81451650 is about 9025.0567865249. The cubic root of 81451650 is about 433.4775686854.

The spelling of 81451650 in words is "eighty-one million, four hundred fifty-one thousand, six hundred fifty".