642002781 has 8 divisors (see below), whose sum is σ = 978289984. Its totient is φ = 366858720.

The previous prime is 642002741. The next prime is 642002797. The reversal of 642002781 is 187200246.

642002781 = T₄₄₈₃ + T₄₄₈₄ + ... + T₄₅₄₅.

642002781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-642002781 is a prime.

It is a super-2 number, since 2×642002781² = 824335141623467922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642002701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15285760 + ... + 15285801.

It is an arithmetic number, because the mean of its divisors is an integer number (122286248).

Almost surely, 2^642002781 is an apocalyptic number.

It is an amenable number.

642002781 is a deficient number, since it is larger than the sum of its proper divisors (336287203).

642002781 is a wasteful number, since it uses less digits than its factorization.

642002781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30571571.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 642002781 is about 25337.7737972380. The cubic root of 642002781 is about 862.6718692992.

The spelling of 642002781 in words is "six hundred forty-two million, two thousand, seven hundred eighty-one".