661949413 has 2 divisors, whose sum is σ = 661949414. Its totient is φ = 661949412.

The previous prime is 661949359. The next prime is 661949429. The reversal of 661949413 is 314949166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 650403009 + 11546404 = 25503^2 + 3398^2 .

It is a cyclic number.

It is not a de Polignac number, because 661949413 - 2²⁵ = 628394981 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661949413.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661949513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330974706 + 330974707.

It is an arithmetic number, because the mean of its divisors is an integer number (330974707).

Almost surely, 2^661949413 is an apocalyptic number.

It is an amenable number.

661949413 is a deficient number, since it is larger than the sum of its proper divisors (1).

661949413 is an equidigital number, since it uses as much as digits as its factorization.

661949413 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 43.

The square root of 661949413 is about 25728.3775819619. The cubic root of 661949413 is about 871.5151353829.

The spelling of 661949413 in words is "six hundred sixty-one million, nine hundred forty-nine thousand, four hundred thirteen".