2690161781 has 2 divisors, whose sum is σ = 2690161782. Its totient is φ = 2690161780.

The previous prime is 2690161769. The next prime is 2690161801. The reversal of 2690161781 is 1871610962.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2635179556 + 54982225 = 51334^2 + 7415^2 .

It is a cyclic number.

It is not a de Polignac number, because 2690161781 - 2⁶ = 2690161717 is a prime.

It is a super-2 number, since 2×2690161781² = 14473940815906183922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2690164781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1345080890 + 1345080891.

It is an arithmetic number, because the mean of its divisors is an integer number (1345080891).

Almost surely, 2^2690161781 is an apocalyptic number.

It is an amenable number.

2690161781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2690161781 is an equidigital number, since it uses as much as digits as its factorization.

2690161781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 41.

The square root of 2690161781 is about 51866.7695253907. The cubic root of 2690161781 is about 1390.7832965859.

The spelling of 2690161781 in words is "two billion, six hundred ninety million, one hundred sixty-one thousand, seven hundred eighty-one".