81761774 has 4 divisors (see below), whose sum is σ = 122642664. Its totient is φ = 40880886.

The previous prime is 81761767. The next prime is 81761809. The reversal of 81761774 is 47716718.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20440442 + ... + 20440445.

It is an arithmetic number, because the mean of its divisors is an integer number (30660666).

Almost surely, 2^81761774 is an apocalyptic number.

81761774 is a deficient number, since it is larger than the sum of its proper divisors (40880890).

81761774 is a wasteful number, since it uses less digits than its factorization.

81761774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40880889.

The product of its digits is 65856, while the sum is 41.

The square root of 81761774 is about 9042.2217402583. The cubic root of 81761774 is about 434.0270216139.

The spelling of 81761774 in words is "eighty-one million, seven hundred sixty-one thousand, seven hundred seventy-four".