81687762090 has 576 divisors, whose sum is σ = 258265687680. Its totient is φ = 18414190080.

The previous prime is 81687762089. The next prime is 81687762097. The reversal of 81687762090 is 9026778618.

81687762090 is a `hidden beast` number, since 8 + 1 + 6 + 8 + 7 + 7 + 620 + 9 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (81687762097) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 749428956 + ... + 749429064.

It is an arithmetic number, because the mean of its divisors is an integer number (448377930).

Almost surely, 2^81687762090 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81687762090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129132843840).

81687762090 is an abundant number, since it is smaller than the sum of its proper divisors (176577925590).

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

81687762090 is a wasteful number, since it uses less digits than its factorization.

81687762090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 81687762090 in words is "eighty-one billion, six hundred eighty-seven million, seven hundred sixty-two thousand, ninety".