81542920550 has 48 divisors (see below), whose sum is σ = 186670573152. Its totient is φ = 25806988800.

The previous prime is 81542920517. The next prime is 81542920553. The reversal of 81542920550 is 5502924518.

It is a super-2 number, since 2×81542920550² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81542920498 and 81542920507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81542920553) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8956211 + ... + 8965310.

It is an arithmetic number, because the mean of its divisors is an integer number (3888970274).

Almost surely, 2^81542920550 is an apocalyptic number.

81542920550 is an abundant number, since it is smaller than the sum of its proper divisors (105127652602).

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

81542920550 is a wasteful number, since it uses less digits than its factorization.

81542920550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17921553 (or 17921548 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 41.

The spelling of 81542920550 in words is "eighty-one billion, five hundred forty-two million, nine hundred twenty thousand, five hundred fifty".