20210618 has 4 divisors (see below), whose sum is σ = 30315930. Its totient is φ = 10105308.

The previous prime is 20210609. The next prime is 20210657. The reversal of 20210618 is 81601202.

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

It can be written as a sum of positive squares in only one way, i.e., 10582009 + 9628609 = 3253^2 + 3103^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20210618.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5052653 + ... + 5052656.

Almost surely, 2^20210618 is an apocalyptic number.

20210618 is a deficient number, since it is larger than the sum of its proper divisors (10105312).

20210618 is a wasteful number, since it uses less digits than its factorization.

20210618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10105311.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 20210618 is about 4495.6220926586. The cubic root of 20210618 is about 272.3912783463.

The spelling of 20210618 in words is "twenty million, two hundred ten thousand, six hundred eighteen".