81907000 has 64 divisors (see below), whose sum is σ = 219061440. Its totient is φ = 28080000.

The previous prime is 81906997. The next prime is 81907013. The reversal of 81907000 is 70918.

It is a Harshad number since it is a multiple of its sum of digits (25).

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 15 ways as a sum of consecutive naturals, for example, 1150 + ... + 12850.

It is an arithmetic number, because the mean of its divisors is an integer number (3422835).

Almost surely, 2^81907000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81907000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109530720).

81907000 is an abundant number, since it is smaller than the sum of its proper divisors (137154440).

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

81907000 is a wasteful number, since it uses less digits than its factorization.

81907000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11729 (or 11715 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 81907000 is about 9050.2486153696. The cubic root of 81907000 is about 434.2838438532.

Adding to 81907000 its reverse (70918), we get a palindrome (81977918).

The spelling of 81907000 in words is "eighty-one million, nine hundred seven thousand".