81963620 has 24 divisors (see below), whose sum is σ = 172314744. Its totient is φ = 32749056.

The previous prime is 81963611. The next prime is 81963631. The reversal of 81963620 is 2636918.

It can be written as a sum of positive squares in 4 ways, for example, as 34739236 + 47224384 = 5894^2 + 6872^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23084 + ... + 26396.

It is an arithmetic number, because the mean of its divisors is an integer number (7179781).

Almost surely, 2^81963620 is an apocalyptic number.

It is an amenable number.

81963620 is an abundant number, since it is smaller than the sum of its proper divisors (90351124).

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

81963620 is a wasteful number, since it uses less digits than its factorization.

81963620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4559 (or 4557 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 81963620 is about 9053.3761658290. The cubic root of 81963620 is about 434.3838901964.

The spelling of 81963620 in words is "eighty-one million, nine hundred sixty-three thousand, six hundred twenty".