611965721 has 2 divisors, whose sum is σ = 611965722. Its totient is φ = 611965720.

The previous prime is 611965693. The next prime is 611965727. The reversal of 611965721 is 127569116.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 593604496 + 18361225 = 24364^2 + 4285^2 .

It is a cyclic number.

It is not a de Polignac number, because 611965721 - 2¹⁴ = 611949337 is a prime.

It is equal to p_31916486 and since 611965721 and 31916486 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (611965727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305982860 + 305982861.

It is an arithmetic number, because the mean of its divisors is an integer number (305982861).

Almost surely, 2^611965721 is an apocalyptic number.

It is an amenable number.

611965721 is a deficient number, since it is larger than the sum of its proper divisors (1).

611965721 is an equidigital number, since it uses as much as digits as its factorization.

611965721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 38.

The square root of 611965721 is about 24737.9409207800. The cubic root of 611965721 is about 849.0026229997.

The spelling of 611965721 in words is "six hundred eleven million, nine hundred sixty-five thousand, seven hundred twenty-one".