81649634 has 16 divisors (see below), whose sum is σ = 134434080. Its totient is φ = 36884160.

The previous prime is 81649621. The next prime is 81649637. The reversal of 81649634 is 43694618.

It is a junction number, because it is equal to n+sod(n) for n = 81649591 and 81649600.

It is not an unprimeable number, because it can be changed into a prime (81649637) 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, 7799 + ... + 14970.

It is an arithmetic number, because the mean of its divisors is an integer number (8402130).

Almost surely, 2^81649634 is an apocalyptic number.

81649634 is a deficient number, since it is larger than the sum of its proper divisors (52784446).

81649634 is a wasteful number, since it uses less digits than its factorization.

81649634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22945.

The product of its digits is 124416, while the sum is 41.

The square root of 81649634 is about 9036.0187029466. The cubic root of 81649634 is about 433.8285015449.

The spelling of 81649634 in words is "eighty-one million, six hundred forty-nine thousand, six hundred thirty-four".