661930447 has 2 divisors, whose sum is σ = 661930448. Its totient is φ = 661930446.

The previous prime is 661930393. The next prime is 661930457. The reversal of 661930447 is 744039166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661930447 - 2¹⁵ = 661897679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661930457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330965223 + 330965224.

It is an arithmetic number, because the mean of its divisors is an integer number (330965224).

Almost surely, 2^661930447 is an apocalyptic number.

661930447 is a deficient number, since it is larger than the sum of its proper divisors (1).

661930447 is an equidigital number, since it uses as much as digits as its factorization.

661930447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 40.

The square root of 661930447 is about 25728.0089979773. The cubic root of 661930447 is about 871.5068118294.

The spelling of 661930447 in words is "six hundred sixty-one million, nine hundred thirty thousand, four hundred forty-seven".