1811901752761 has 9 divisors (see below), whose sum is σ = 1830905661549. Its totient is φ = 1793093130624.

The previous prime is 1811901752737. The next prime is 1811901752767. The reversal of 1811901752761 is 1672571091181.

It is a happy number.

The square root of 1811901752761 is 1346069.

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

It can be written as a sum of positive squares in 4 ways, for example, as 510340213161 + 1301561539600 = 714381^2 + 1140860^2 .

It is not a de Polignac number, because 1811901752761 - 2⁵ = 1811901752729 is a prime.

It is a super-2 number, since 2×1811901752761² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1811901752767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 130561755 + ... + 130575631.

Almost surely, 2^{1811901752761} is an apocalyptic number.

1811901752761 is the 1346069-th square number.

1811901752761 is the 673035-th centered octagonal number.

It is an amenable number.

1811901752761 is a deficient number, since it is larger than the sum of its proper divisors (19003908788).

1811901752761 is an frugal number, since it uses more digits than its factorization.

1811901752761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27948 (or 13974 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 49.

Multiplying 1811901752761 by its sum of digits (49), we get a square (88783185885289 = 9422483²).

The spelling of 1811901752761 in words is "one trillion, eight hundred eleven billion, nine hundred one million, seven hundred fifty-two thousand, seven hundred sixty-one".