81775634 has 4 divisors (see below), whose sum is σ = 122663454. Its totient is φ = 40887816.

The previous prime is 81775609. The next prime is 81775643. The reversal of 81775634 is 43657718.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 79263409 + 2512225 = 8903^2 + 1585^2 .

It is a super-2 number, since 2×81775634² = 13374508632203912, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81775591 and 81775600.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20443907 + ... + 20443910.

Almost surely, 2^81775634 is an apocalyptic number.

81775634 is a deficient number, since it is larger than the sum of its proper divisors (40887820).

81775634 is a wasteful number, since it uses less digits than its factorization.

81775634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40887819.

The product of its digits is 141120, while the sum is 41.

The square root of 81775634 is about 9042.9881123443. The cubic root of 81775634 is about 434.0515451956.

The spelling of 81775634 in words is "eighty-one million, seven hundred seventy-five thousand, six hundred thirty-four".