2031551681 has 4 divisors (see below), whose sum is σ = 2081101764. Its totient is φ = 1982001600.

The previous prime is 2031551657. The next prime is 2031551693. The reversal of 2031551681 is 1861551302.

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 168766081 + 1862785600 = 12991^2 + 43160^2 .

It is a cyclic number.

It is not a de Polignac number, because 2031551681 - 2⁶ = 2031551617 is a prime.

It is a super-2 number, since 2×2031551681² = 8254404465147851522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2031551881) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 24774980 + ... + 24775061.

It is an arithmetic number, because the mean of its divisors is an integer number (520275441).

Almost surely, 2^2031551681 is an apocalyptic number.

It is an amenable number.

2031551681 is a deficient number, since it is larger than the sum of its proper divisors (49550083).

2031551681 is an equidigital number, since it uses as much as digits as its factorization.

2031551681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49550082.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 2031551681 is about 45072.7376692386. The cubic root of 2031551681 is about 1266.5119493007.

The spelling of 2031551681 in words is "two billion, thirty-one million, five hundred fifty-one thousand, six hundred eighty-one".