61643513 has 8 divisors (see below), whose sum is σ = 65353032. Its totient is φ = 57943296.

The previous prime is 61643507. The next prime is 61643539. The reversal of 61643513 is 31534616.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10778089 + 50865424 = 3283^2 + 7132^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61643513 - 2⁴ = 61643497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61643563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15131 + ... + 18767.

It is an arithmetic number, because the mean of its divisors is an integer number (8169129).

Almost surely, 2^61643513 is an apocalyptic number.

It is an amenable number.

61643513 is a deficient number, since it is larger than the sum of its proper divisors (3709519).

61643513 is a wasteful number, since it uses less digits than its factorization.

61643513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4651.

The product of its digits is 6480, while the sum is 29.

The square root of 61643513 is about 7851.3382935650. The cubic root of 61643513 is about 395.0291342074.

The spelling of 61643513 in words is "sixty-one million, six hundred forty-three thousand, five hundred thirteen".