81260661064 has 32 divisors (see below), whose sum is σ = 166492584000. Its totient is φ = 36874976320.

The previous prime is 81260661061. The next prime is 81260661103. The reversal of 81260661064 is 46016606218.

It is a happy number.

It is a super-2 number, since 2×81260661064² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81260661061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 718087 + ... + 823510.

It is an arithmetic number, because the mean of its divisors is an integer number (5202893250).

Almost surely, 2^81260661064 is an apocalyptic number.

It is an amenable number.

81260661064 is an abundant number, since it is smaller than the sum of its proper divisors (85231922936).

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

81260661064 is a wasteful number, since it uses less digits than its factorization.

81260661064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1542213 (or 1542209 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 40.

The spelling of 81260661064 in words is "eighty-one billion, two hundred sixty million, six hundred sixty-one thousand, sixty-four".