81923141 has 4 divisors (see below), whose sum is σ = 81981900. Its totient is φ = 81864384.

The previous prime is 81923099. The next prime is 81923189. The reversal of 81923141 is 14132918.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4218916 + 77704225 = 2054^2 + 8815^2 .

It is a cyclic number.

It is not a de Polignac number, because 81923141 - 2²² = 77728837 is a prime.

It is a super-2 number, since 2×81923141² = 13422802062611762, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81923341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27236 + ... + 30093.

It is an arithmetic number, because the mean of its divisors is an integer number (20495475).

Almost surely, 2^81923141 is an apocalyptic number.

It is an amenable number.

81923141 is a deficient number, since it is larger than the sum of its proper divisors (58759).

81923141 is a wasteful number, since it uses less digits than its factorization.

81923141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58758.

The product of its digits is 1728, while the sum is 29.

The square root of 81923141 is about 9051.1403148996. The cubic root of 81923141 is about 434.3123693562.

The spelling of 81923141 in words is "eighty-one million, nine hundred twenty-three thousand, one hundred forty-one".