661541357 has 2 divisors, whose sum is σ = 661541358. Its totient is φ = 661541356.

The previous prime is 661541269. The next prime is 661541381. The reversal of 661541357 is 753145166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 571879396 + 89661961 = 23914^2 + 9469^2 .

It is a cyclic number.

It is not a de Polignac number, because 661541357 - 2¹⁴ = 661524973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661541357.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661541057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330770678 + 330770679.

It is an arithmetic number, because the mean of its divisors is an integer number (330770679).

Almost surely, 2^661541357 is an apocalyptic number.

It is an amenable number.

661541357 is a deficient number, since it is larger than the sum of its proper divisors (1).

661541357 is an equidigital number, since it uses as much as digits as its factorization.

661541357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75600, while the sum is 38.

The square root of 661541357 is about 25720.4462830644. The cubic root of 661541357 is about 871.3360179291.

The spelling of 661541357 in words is "six hundred sixty-one million, five hundred forty-one thousand, three hundred fifty-seven".