642973421389 has 4 divisors (see below), whose sum is σ = 692432915356. Its totient is φ = 593513927424.

The previous prime is 642973421383. The next prime is 642973421393. The reversal of 642973421389 is 983124379246.

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

It can be written as a sum of positive squares in 2 ways, for example, as 408410464900 + 234562956489 = 639070^2 + 484317^2 .

It is a cyclic number.

It is not a de Polignac number, because 642973421389 - 2⁷ = 642973421261 is a prime.

It is a super-2 number, since 2×642973421389² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642973421383) 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, 24729746964 + ... + 24729746989.

It is an arithmetic number, because the mean of its divisors is an integer number (173108228839).

Almost surely, 2^642973421389 is an apocalyptic number.

It is an amenable number.

642973421389 is a deficient number, since it is larger than the sum of its proper divisors (49459493967).

642973421389 is a wasteful number, since it uses less digits than its factorization.

642973421389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49459493966.

The product of its digits is 15676416, while the sum is 58.

The spelling of 642973421389 in words is "six hundred forty-two billion, nine hundred seventy-three million, four hundred twenty-one thousand, three hundred eighty-nine".