81616570474 has 8 divisors (see below), whose sum is σ = 122811054948. Its totient is φ = 40679552160.

The previous prime is 81616570457. The next prime is 81616570517. The reversal of 81616570474 is 47407561618.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 81615919225 + 651249 = 285685^2 + 807^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81616570474² (a number of 23 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 64365747 + ... + 64367014.

Almost surely, 2^81616570474 is an apocalyptic number.

81616570474 is a deficient number, since it is larger than the sum of its proper divisors (41194484474).

81616570474 is a wasteful number, since it uses less digits than its factorization.

81616570474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128733080.

The product of its (nonzero) digits is 1128960, while the sum is 49.

The spelling of 81616570474 in words is "eighty-one billion, six hundred sixteen million, five hundred seventy thousand, four hundred seventy-four".