642721786363 has 4 divisors (see below), whose sum is σ = 642934399968. Its totient is φ = 642509172760.

The previous prime is 642721786327. The next prime is 642721786393. The reversal of 642721786363 is 363687127246.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 642721786363 - 2¹⁷ = 642721655291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642721786393) 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, 106302268 + ... + 106308313.

It is an arithmetic number, because the mean of its divisors is an integer number (160733599992).

Almost surely, 2^642721786363 is an apocalyptic number.

642721786363 is a deficient number, since it is larger than the sum of its proper divisors (212613605).

642721786363 is a wasteful number, since it uses less digits than its factorization.

642721786363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212613604.

The product of its digits is 12192768, while the sum is 55.

The spelling of 642721786363 in words is "six hundred forty-two billion, seven hundred twenty-one million, seven hundred eighty-six thousand, three hundred sixty-three".