639920704973 has 4 divisors (see below), whose sum is σ = 698095314528. Its totient is φ = 581746095420.

The previous prime is 639920704967. The next prime is 639920704979. The reversal of 639920704973 is 379407029936.

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 an interprime number because it is at equal distance from previous prime (639920704967) and next prime (639920704979).

It is a cyclic number.

It is not a de Polignac number, because 639920704973 - 2¹⁸ = 639920442829 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 (639920704979) 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, 29087304761 + ... + 29087304782.

It is an arithmetic number, because the mean of its divisors is an integer number (174523828632).

Almost surely, 2^639920704973 is an apocalyptic number.

It is an amenable number.

639920704973 is a deficient number, since it is larger than the sum of its proper divisors (58174609555).

639920704973 is a wasteful number, since it uses less digits than its factorization.

639920704973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58174609554.

The product of its (nonzero) digits is 15431472, while the sum is 59.

The spelling of 639920704973 in words is "six hundred thirty-nine billion, nine hundred twenty million, seven hundred four thousand, nine hundred seventy-three".