3966921221 has 2 divisors, whose sum is σ = 3966921222. Its totient is φ = 3966921220.

The previous prime is 3966921197. The next prime is 3966921311. The reversal of 3966921221 is 1221296693.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3757077025 + 209844196 = 61295^2 + 14486^2 .

It is an emirp because it is prime and its reverse (1221296693) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3966921221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3966921121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1983460610 + 1983460611.

It is an arithmetic number, because the mean of its divisors is an integer number (1983460611).

Almost surely, 2^3966921221 is an apocalyptic number.

It is an amenable number.

3966921221 is a deficient number, since it is larger than the sum of its proper divisors (1).

3966921221 is an equidigital number, since it uses as much as digits as its factorization.

3966921221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 3966921221 is about 62983.4995931474. The cubic root of 3966921221 is about 1583.0131600904.

The spelling of 3966921221 in words is "three billion, nine hundred sixty-six million, nine hundred twenty-one thousand, two hundred twenty-one".