81637950 has 48 divisors (see below), whose sum is σ = 203736960. Its totient is φ = 21633120.

The previous prime is 81637949. The next prime is 81637981. The reversal of 81637950 is 5973618.

It is a junction number, because it is equal to n+sod(n) for n = 81637899 and 81637908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23421 + ... + 26679.

It is an arithmetic number, because the mean of its divisors is an integer number (4244520).

Almost surely, 2^81637950 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81637950, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101868480).

81637950 is an abundant number, since it is smaller than the sum of its proper divisors (122099010).

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

81637950 is a wasteful number, since it uses less digits than its factorization.

81637950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3441 (or 3436 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 81637950 is about 9035.3721561428. The cubic root of 81637950 is about 433.8078070492.

The spelling of 81637950 in words is "eighty-one million, six hundred thirty-seven thousand, nine hundred fifty".