39981549 has 4 divisors (see below), whose sum is σ = 53308736. Its totient is φ = 26654364.

The previous prime is 39981509. The next prime is 39981551. The reversal of 39981549 is 94518993.

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: 94518993 = 3 ⋅31506331.

It is not a de Polignac number, because 39981549 - 2⁷ = 39981421 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 39981498 and 39981507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39981509) 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, 6663589 + ... + 6663594.

It is an arithmetic number, because the mean of its divisors is an integer number (13327184).

Almost surely, 2^39981549 is an apocalyptic number.

It is an amenable number.

39981549 is a deficient number, since it is larger than the sum of its proper divisors (13327187).

39981549 is a wasteful number, since it uses less digits than its factorization.

39981549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13327186.

The product of its digits is 349920, while the sum is 48.

The square root of 39981549 is about 6323.0964724571. The cubic root of 39981549 is about 341.9425966376.

The spelling of 39981549 in words is "thirty-nine million, nine hundred eighty-one thousand, five hundred forty-nine".