6406961381 has 2 divisors, whose sum is σ = 6406961382. Its totient is φ = 6406961380.

The previous prime is 6406961371. The next prime is 6406961401. The reversal of 6406961381 is 1831696046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6374585281 + 32376100 = 79841^2 + 5690^2 .

It is a cyclic number.

It is not a de Polignac number, because 6406961381 - 2³⁰ = 5333219557 is a prime.

It is a super-2 number, since 2×6406961381² = 82098308275250854322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6406961311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3203480690 + 3203480691.

It is an arithmetic number, because the mean of its divisors is an integer number (3203480691).

Almost surely, 2^6406961381 is an apocalyptic number.

It is an amenable number.

6406961381 is a deficient number, since it is larger than the sum of its proper divisors (1).

6406961381 is an equidigital number, since it uses as much as digits as its factorization.

6406961381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 6406961381 is about 80043.4968064239. The cubic root of 6406961381 is about 1857.3084534454.

The spelling of 6406961381 in words is "six billion, four hundred six million, nine hundred sixty-one thousand, three hundred eighty-one".