81653634000 has 480 divisors, whose sum is σ = 300124790784. Its totient is φ = 20650291200.

The previous prime is 81653633989. The next prime is 81653634011. The reversal of 81653634000 is 43635618.

81653634000 is a `hidden beast` number, since 8 + 16 + 5 + 3 + 634 + 0 + 0 + 0 = 666.

It is a Cunningham number, because it is equal to 285751²-1.

It is an interprime number because it is at equal distance from previous prime (81653633989) and next prime (81653634011).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 52577224 + ... + 52578776.

Almost surely, 2^81653634000 is an apocalyptic number.

81653634000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81653634000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150062395392).

81653634000 is an abundant number, since it is smaller than the sum of its proper divisors (218471156784).

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

81653634000 is a wasteful number, since it uses less digits than its factorization.

81653634000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1732 (or 1713 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 81653634000 in words is "eighty-one billion, six hundred fifty-three million, six hundred thirty-four thousand".