6961879921 has 2 divisors, whose sum is σ = 6961879922. Its totient is φ = 6961879920.

The previous prime is 6961879853. The next prime is 6961879931. The reversal of 6961879921 is 1299781696.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4432896400 + 2528983521 = 66580^2 + 50289^2 .

It is a cyclic number.

It is not a de Polignac number, because 6961879921 - 2⁹ = 6961879409 is a prime.

It is not a weakly prime, because it can be changed into another prime (6961879931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3480939960 + 3480939961.

It is an arithmetic number, because the mean of its divisors is an integer number (3480939961).

Almost surely, 2^6961879921 is an apocalyptic number.

It is an amenable number.

6961879921 is a deficient number, since it is larger than the sum of its proper divisors (1).

6961879921 is an equidigital number, since it uses as much as digits as its factorization.

6961879921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 58.

The square root of 6961879921 is about 83437.8806118660. The cubic root of 6961879921 is about 1909.4524275748.

The spelling of 6961879921 in words is "six billion, nine hundred sixty-one million, eight hundred seventy-nine thousand, nine hundred twenty-one".