3951285721 has 2 divisors, whose sum is σ = 3951285722. Its totient is φ = 3951285720.

The previous prime is 3951285703. The next prime is 3951285739. The reversal of 3951285721 is 1275821593.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (3951285703) and next prime (3951285739).

It can be written as a sum of positive squares in only one way, i.e., 2140357696 + 1810928025 = 46264^2 + 42555^2 .

It is a cyclic number.

It is not a de Polignac number, because 3951285721 - 2⁷ = 3951285593 is a prime.

It is a super-2 number, since 2×3951285721² = 31225317697956979682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3951285791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1975642860 + 1975642861.

It is an arithmetic number, because the mean of its divisors is an integer number (1975642861).

Almost surely, 2^3951285721 is an apocalyptic number.

It is an amenable number.

3951285721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3951285721 is an equidigital number, since it uses as much as digits as its factorization.

3951285721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 151200, while the sum is 43.

The square root of 3951285721 is about 62859.2532647342. The cubic root of 3951285721 is about 1580.9306221067.

The spelling of 3951285721 in words is "three billion, nine hundred fifty-one million, two hundred eighty-five thousand, seven hundred twenty-one".