81637633 has 8 divisors (see below), whose sum is σ = 101782080. Its totient is φ = 63613680.

The previous prime is 81637631. The next prime is 81637657. The reversal of 81637633 is 33673618.

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 81637633 - 2¹ = 81637631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81637592 and 81637601.

It is not an unprimeable number, because it can be changed into a prime (81637631) 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, 530038 + ... + 530191.

It is an arithmetic number, because the mean of its divisors is an integer number (12722760).

Almost surely, 2^81637633 is an apocalyptic number.

It is an amenable number.

81637633 is a deficient number, since it is larger than the sum of its proper divisors (20144447).

81637633 is a wasteful number, since it uses less digits than its factorization.

81637633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060247.

The product of its digits is 54432, while the sum is 37.

The square root of 81637633 is about 9035.3546139595. The cubic root of 81637633 is about 433.8072455568.

The spelling of 81637633 in words is "eighty-one million, six hundred thirty-seven thousand, six hundred thirty-three".