2140987781 has 2 divisors, whose sum is σ = 2140987782. Its totient is φ = 2140987780.

The previous prime is 2140987741. The next prime is 2140987787. The reversal of 2140987781 is 1877890412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1698264100 + 442723681 = 41210^2 + 21041^2 .

It is a cyclic number.

It is not a de Polignac number, because 2140987781 - 2¹⁴ = 2140971397 is a prime.

It is a super-2 number, since 2×2140987781² = 9167657356782607922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2140987787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1070493890 + 1070493891.

It is an arithmetic number, because the mean of its divisors is an integer number (1070493891).

Almost surely, 2^2140987781 is an apocalyptic number.

It is an amenable number.

2140987781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2140987781 is an equidigital number, since it uses as much as digits as its factorization.

2140987781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 225792, while the sum is 47.

The square root of 2140987781 is about 46270.8091673357. The cubic root of 2140987781 is about 1288.8569850376.

The spelling of 2140987781 in words is "two billion, one hundred forty million, nine hundred eighty-seven thousand, seven hundred eighty-one".