81954634 has 4 divisors (see below), whose sum is σ = 122931954. Its totient is φ = 40977316.

The previous prime is 81954629. The next prime is 81954641. The reversal of 81954634 is 43645918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 43645918 = 2 ⋅21822959.

It can be written as a sum of positive squares in only one way, i.e., 68973025 + 12981609 = 8305^2 + 3603^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20488657 + ... + 20488660.

Almost surely, 2^81954634 is an apocalyptic number.

81954634 is a deficient number, since it is larger than the sum of its proper divisors (40977320).

81954634 is a wasteful number, since it uses less digits than its factorization.

81954634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40977319.

The product of its digits is 103680, while the sum is 40.

The square root of 81954634 is about 9052.8798732779. The cubic root of 81954634 is about 434.3680152009.

The spelling of 81954634 in words is "eighty-one million, nine hundred fifty-four thousand, six hundred thirty-four".