61643539 has 2 divisors, whose sum is σ = 61643540. Its totient is φ = 61643538.

The previous prime is 61643507. The next prime is 61643563. The reversal of 61643539 is 93534616.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61643539 - 2⁵ = 61643507 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61643498 and 61643507.

It is not a weakly prime, because it can be changed into another prime (61643579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30821769 + 30821770.

It is an arithmetic number, because the mean of its divisors is an integer number (30821770).

Almost surely, 2^61643539 is an apocalyptic number.

61643539 is a deficient number, since it is larger than the sum of its proper divisors (1).

61643539 is an equidigital number, since it uses as much as digits as its factorization.

61643539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 37.

The square root of 61643539 is about 7851.3399493335. The cubic root of 61643539 is about 395.0291897459.

The spelling of 61643539 in words is "sixty-one million, six hundred forty-three thousand, five hundred thirty-nine".