81630247 has 2 divisors, whose sum is σ = 81630248. Its totient is φ = 81630246.

The previous prime is 81630181. The next prime is 81630257. The reversal of 81630247 is 74203618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81630247 - 2²³ = 73241639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81630257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40815123 + 40815124.

It is an arithmetic number, because the mean of its divisors is an integer number (40815124).

Almost surely, 2^81630247 is an apocalyptic number.

81630247 is a deficient number, since it is larger than the sum of its proper divisors (1).

81630247 is an equidigital number, since it uses as much as digits as its factorization.

81630247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 81630247 is about 9034.9458769823. The cubic root of 81630247 is about 433.7941625507.

The spelling of 81630247 in words is "eighty-one million, six hundred thirty thousand, two hundred forty-seven".