81717917946 has 32 divisors (see below), whose sum is σ = 186995910528. Its totient is φ = 23321464320.

The previous prime is 81717917923. The next prime is 81717917947. The reversal of 81717917946 is 64971971718.

It is a super-2 number, since 2×81717917946² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81717917946.

It is not an unprimeable number, because it can be changed into a prime (81717917947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1067235 + ... + 1141238.

It is an arithmetic number, because the mean of its divisors is an integer number (5843622204).

Almost surely, 2^81717917946 is an apocalyptic number.

81717917946 is an abundant number, since it is smaller than the sum of its proper divisors (105277992582).

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

81717917946 is a wasteful number, since it uses less digits than its factorization.

81717917946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2209366.

The product of its digits is 5334336, while the sum is 60.

The spelling of 81717917946 in words is "eighty-one billion, seven hundred seventeen million, nine hundred seventeen thousand, nine hundred forty-six".