81737849 has 4 divisors (see below), whose sum is σ = 81924480. Its totient is φ = 81551220.

The previous prime is 81737839. The next prime is 81737893. The reversal of 81737849 is 94873718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94873718 = 2 ⋅47436859.

It is a cyclic number.

It is not a de Polignac number, because 81737849 - 2¹² = 81733753 is a prime.

It is a super-3 number, since 3×81737849³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81737839) 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, 92657 + ... + 93534.

It is an arithmetic number, because the mean of its divisors is an integer number (20481120).

Almost surely, 2^81737849 is an apocalyptic number.

It is an amenable number.

81737849 is a deficient number, since it is larger than the sum of its proper divisors (186631).

81737849 is a wasteful number, since it uses less digits than its factorization.

81737849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186630.

The product of its digits is 338688, while the sum is 47.

The square root of 81737849 is about 9040.8986832062. The cubic root of 81737849 is about 433.9846827188.

The spelling of 81737849 in words is "eighty-one million, seven hundred thirty-seven thousand, eight hundred forty-nine".