3997699781 has 2 divisors, whose sum is σ = 3997699782. Its totient is φ = 3997699780.

The previous prime is 3997699763. The next prime is 3997699789. The reversal of 3997699781 is 1879967993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3989943556 + 7756225 = 63166^2 + 2785^2 .

It is a cyclic number.

It is not a de Polignac number, because 3997699781 - 2¹⁸ = 3997437637 is a prime.

It is a super-2 number, since 2×3997699781² = 31963207078014895922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3997699789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1998849890 + 1998849891.

It is an arithmetic number, because the mean of its divisors is an integer number (1998849891).

Almost surely, 2^3997699781 is an apocalyptic number.

It is an amenable number.

3997699781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3997699781 is an equidigital number, since it uses as much as digits as its factorization.

3997699781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46294416, while the sum is 68.

The square root of 3997699781 is about 63227.3657604047. The cubic root of 3997699781 is about 1587.0967127851.

The spelling of 3997699781 in words is "three billion, nine hundred ninety-seven million, six hundred ninety-nine thousand, seven hundred eighty-one".