661434247 has 2 divisors, whose sum is σ = 661434248. Its totient is φ = 661434246.

The previous prime is 661434229. The next prime is 661434287. The reversal of 661434247 is 742434166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661434247 - 2¹⁵ = 661401479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661434287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330717123 + 330717124.

It is an arithmetic number, because the mean of its divisors is an integer number (330717124).

Almost surely, 2^661434247 is an apocalyptic number.

661434247 is a deficient number, since it is larger than the sum of its proper divisors (1).

661434247 is an equidigital number, since it uses as much as digits as its factorization.

661434247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 37.

The square root of 661434247 is about 25718.3640031787. The cubic root of 661434247 is about 871.2889894568.

The spelling of 661434247 in words is "six hundred sixty-one million, four hundred thirty-four thousand, two hundred forty-seven".