1021640189 has 4 divisors (see below), whose sum is σ = 1049252124. Its totient is φ = 994028256.

The previous prime is 1021640171. The next prime is 1021640209. The reversal of 1021640189 is 9810461201.

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 480705625 + 540934564 = 21925^2 + 23258^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021640189 - 2⁸ = 1021639933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021640129) 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, 13805912 + ... + 13805985.

It is an arithmetic number, because the mean of its divisors is an integer number (262313031).

Almost surely, 2^1021640189 is an apocalyptic number.

It is an amenable number.

1021640189 is a deficient number, since it is larger than the sum of its proper divisors (27611935).

1021640189 is an equidigital number, since it uses as much as digits as its factorization.

1021640189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27611934.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 1021640189 is about 31963.1066856775. The cubic root of 1021640189 is about 1007.1619799215.

It can be divided in two parts, 10216 and 40189, that added together give a palindrome (50405).

The spelling of 1021640189 in words is "one billion, twenty-one million, six hundred forty thousand, one hundred eighty-nine".