81787292007826 has 32 divisors (see below), whose sum is σ = 124002320568768. Its totient is φ = 40454582138880.

The previous prime is 81787292007803. The next prime is 81787292007853. The reversal of 81787292007826 is 62870029278718.

It is a happy number.

It is a super-2 number, since 2×81787292007826² (a number of 29 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, 1111641621 + ... + 1111715191.

It is an arithmetic number, because the mean of its divisors is an integer number (3875072517774).

Almost surely, 2^{81787292007826} is an apocalyptic number.

81787292007826 is a deficient number, since it is larger than the sum of its proper divisors (42215028560942).

81787292007826 is a wasteful number, since it uses less digits than its factorization.

81787292007826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82986.

The product of its (nonzero) digits is 75866112, while the sum is 67.

The spelling of 81787292007826 in words is "eighty-one trillion, seven hundred eighty-seven billion, two hundred ninety-two million, seven thousand, eight hundred twenty-six".