1836537225721 has 27 divisors (see below), whose sum is σ = 2144699599567. Its totient is φ = 1571151919040.

The previous prime is 1836537225713. The next prime is 1836537225779. The reversal of 1836537225721 is 1275227356381.

It is a happy number.

The square root of 1836537225721 is 1355189.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1429830020025 + 406707205696 = 1195755^2 + 637736^2 .

It is not a de Polignac number, because 1836537225721 - 2³ = 1836537225713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1836537225701) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 253416720 + ... + 253423966.

Almost surely, 2^{1836537225721} is an apocalyptic number.

1836537225721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1836537225721 is the 1355189-th square number.

1836537225721 is the 677595-th centered octagonal number.

It is an amenable number.

1836537225721 is a deficient number, since it is larger than the sum of its proper divisors (308162373846).

1836537225721 is an frugal number, since it uses more digits than its factorization.

1836537225721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14550 (or 7275 counting only the distinct ones).

The product of its digits is 4233600, while the sum is 52.

The spelling of 1836537225721 in words is "one trillion, eight hundred thirty-six billion, five hundred thirty-seven million, two hundred twenty-five thousand, seven hundred twenty-one".