642818853 has 12 divisors (see below), whose sum is σ = 931688940. Its totient is φ = 427081536.

The previous prime is 642818831. The next prime is 642818863. The reversal of 642818853 is 358818246.

It can be written as a sum of positive squares in 2 ways, for example, as 597215844 + 45603009 = 24438^2 + 6753^2 .

It is not a de Polignac number, because 642818853 - 2¹⁸ = 642556709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 642818799 and 642818808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642818863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 119248 + ... + 124521.

It is an arithmetic number, because the mean of its divisors is an integer number (77640745).

Almost surely, 2^642818853 is an apocalyptic number.

It is an amenable number.

642818853 is a deficient number, since it is larger than the sum of its proper divisors (288870087).

642818853 is a wasteful number, since it uses less digits than its factorization.

642818853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244068 (or 244065 counting only the distinct ones).

The product of its digits is 368640, while the sum is 45.

The square root of 642818853 is about 25353.8725444457. The cubic root of 642818853 is about 863.0372385754.

It can be divided in two parts, 6428 and 18853, that added together give a square (25281 = 159²).

The spelling of 642818853 in words is "six hundred forty-two million, eight hundred eighteen thousand, eight hundred fifty-three".