81762291 has 20 divisors (see below), whose sum is σ = 131535712. Its totient is φ = 50314608.

The previous prime is 81762287. The next prime is 81762313. The reversal of 81762291 is 19226718.

It is not a de Polignac number, because 81762291 - 2² = 81762287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81762391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 37771 + ... + 39876.

Almost surely, 2^81762291 is an apocalyptic number.

81762291 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81762291 is a deficient number, since it is larger than the sum of its proper divisors (49773421).

81762291 is a wasteful number, since it uses less digits than its factorization.

81762291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77672 (or 77663 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 81762291 is about 9042.2503283198. The cubic root of 81762291 is about 434.0279364321.

The spelling of 81762291 in words is "eighty-one million, seven hundred sixty-two thousand, two hundred ninety-one".