39978439750646 has 4 divisors (see below), whose sum is σ = 59967659625972. Its totient is φ = 19989219875322.

The previous prime is 39978439750591. The next prime is 39978439750663. The reversal of 39978439750646 is 64605793487993.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9994609937660 + ... + 9994609937663.

It is an arithmetic number, because the mean of its divisors is an integer number (14991914906493).

Almost surely, 2^{39978439750646} is an apocalyptic number.

39978439750646 is a deficient number, since it is larger than the sum of its proper divisors (19989219875326).

39978439750646 is a wasteful number, since it uses less digits than its factorization.

39978439750646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19989219875325.

The product of its (nonzero) digits is 7407106560, while the sum is 80.

The spelling of 39978439750646 in words is "thirty-nine trillion, nine hundred seventy-eight billion, four hundred thirty-nine million, seven hundred fifty thousand, six hundred forty-six".