81630947 has 8 divisors (see below), whose sum is σ = 82864320. Its totient is φ = 80407080.

The previous prime is 81630929. The next prime is 81630953. The reversal of 81630947 is 74903618.

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

It is a cyclic number.

It is not a de Polignac number, because 81630947 - 2⁸ = 81630691 is a prime.

It is a super-2 number, since 2×81630947² = 13327223016233618, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81630947.

It is not an unprimeable number, because it can be changed into a prime (81630977) 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, 15968 + ... + 20450.

It is an arithmetic number, because the mean of its divisors is an integer number (10358040).

Almost surely, 2^81630947 is an apocalyptic number.

81630947 is a deficient number, since it is larger than the sum of its proper divisors (1233373).

81630947 is a wasteful number, since it uses less digits than its factorization.

81630947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4753.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 81630947 is about 9034.9846153715. The cubic root of 81630947 is about 433.7954025120.

The spelling of 81630947 in words is "eighty-one million, six hundred thirty thousand, nine hundred forty-seven".