81225562187 has 16 divisors (see below), whose sum is σ = 102270898944. Its totient is φ = 62665980000.

The previous prime is 81225562177. The next prime is 81225562189. The reversal of 81225562187 is 78126552218.

It is a cyclic number.

It is not a de Polignac number, because 81225562187 - 2¹² = 81225558091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81225562189) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5214389 + ... + 5229942.

It is an arithmetic number, because the mean of its divisors is an integer number (6391931184).

Almost surely, 2^81225562187 is an apocalyptic number.

81225562187 is a deficient number, since it is larger than the sum of its proper divisors (21045336757).

81225562187 is a wasteful number, since it uses less digits than its factorization.

81225562187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10444450.

The product of its digits is 537600, while the sum is 47.

The spelling of 81225562187 in words is "eighty-one billion, two hundred twenty-five million, five hundred sixty-two thousand, one hundred eighty-seven".