39393821 has 4 divisors (see below), whose sum is σ = 41467200. Its totient is φ = 37320444.

The previous prime is 39393817. The next prime is 39393829. The reversal of 39393821 is 12839393.

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: 12839393 = 7 ⋅1834199.

It is a cyclic number.

It is not a de Polignac number, because 39393821 - 2² = 39393817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39393829) 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, 1036661 + ... + 1036698.

It is an arithmetic number, because the mean of its divisors is an integer number (10366800).

Almost surely, 2^39393821 is an apocalyptic number.

It is an amenable number.

39393821 is a deficient number, since it is larger than the sum of its proper divisors (2073379).

39393821 is a wasteful number, since it uses less digits than its factorization.

39393821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2073378.

The product of its digits is 34992, while the sum is 38.

The square root of 39393821 is about 6276.4497130145. The cubic root of 39393821 is about 340.2588023772.

The spelling of 39393821 in words is "thirty-nine million, three hundred ninety-three thousand, eight hundred twenty-one".