81635255890 has 16 divisors (see below), whose sum is σ = 147275169408. Its totient is φ = 32580389296.

The previous prime is 81635255869. The next prime is 81635255893. The reversal of 81635255890 is 9855253618.

It is not an unprimeable number, because it can be changed into a prime (81635255893) 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, 9209482 + ... + 9218341.

It is an arithmetic number, because the mean of its divisors is an integer number (9204698088).

Almost surely, 2^81635255890 is an apocalyptic number.

81635255890 is a deficient number, since it is larger than the sum of its proper divisors (65639913518).

81635255890 is a wasteful number, since it uses less digits than its factorization.

81635255890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18428273.

The product of its (nonzero) digits is 2592000, while the sum is 52.

The spelling of 81635255890 in words is "eighty-one billion, six hundred thirty-five million, two hundred fifty-five thousand, eight hundred ninety".