81491156106 has 32 divisors (see below), whose sum is σ = 172715146560. Its totient is φ = 25544276736.

The previous prime is 81491156053. The next prime is 81491156167. The reversal of 81491156106 is 60165119418.

It is a happy number.

It is a super-2 number, since 2×81491156106² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 215461 + ... + 457608.

It is an arithmetic number, because the mean of its divisors is an integer number (5397348330).

Almost surely, 2^81491156106 is an apocalyptic number.

81491156106 is an abundant number, since it is smaller than the sum of its proper divisors (91223990454).

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

81491156106 is a wasteful number, since it uses less digits than its factorization.

81491156106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674278.

The product of its (nonzero) digits is 51840, while the sum is 42.

The spelling of 81491156106 in words is "eighty-one billion, four hundred ninety-one million, one hundred fifty-six thousand, one hundred six".