642724401997 has 4 divisors (see below), whose sum is σ = 645168221280. Its totient is φ = 640280582716.

The previous prime is 642724401959. The next prime is 642724402013. The reversal of 642724401997 is 799104427246.

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 a de Polignac number, because none of the positive numbers 2^k-642724401997 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 (642724471997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1221909247 + ... + 1221909772.

It is an arithmetic number, because the mean of its divisors is an integer number (161292055320).

Almost surely, 2^642724401997 is an apocalyptic number.

It is an amenable number.

642724401997 is a deficient number, since it is larger than the sum of its proper divisors (2443819283).

642724401997 is a wasteful number, since it uses less digits than its factorization.

642724401997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2443819282.

The product of its (nonzero) digits is 6096384, while the sum is 55.

The spelling of 642724401997 in words is "six hundred forty-two billion, seven hundred twenty-four million, four hundred one thousand, nine hundred ninety-seven".