39718921 has 4 divisors (see below), whose sum is σ = 43329744. Its totient is φ = 36108100.

The previous prime is 39718883. The next prime is 39718933. The reversal of 39718921 is 12981793.

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.

It is a cyclic number.

It is not a de Polignac number, because 39718921 - 2⁷ = 39718793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39718961) 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, 1805395 + ... + 1805416.

It is an arithmetic number, because the mean of its divisors is an integer number (10832436).

Almost surely, 2^39718921 is an apocalyptic number.

It is an amenable number.

39718921 is a deficient number, since it is larger than the sum of its proper divisors (3610823).

39718921 is a wasteful number, since it uses less digits than its factorization.

39718921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3610822.

The product of its digits is 27216, while the sum is 40.

The square root of 39718921 is about 6302.2948994791. The cubic root of 39718921 is about 341.1922417420.

The spelling of 39718921 in words is "thirty-nine million, seven hundred eighteen thousand, nine hundred twenty-one".