61643645 has 16 divisors (see below), whose sum is σ = 84913920. Its totient is φ = 42082944.

The previous prime is 61643599. The next prime is 61643651. The reversal of 61643645 is 54634616.

It is a cyclic number.

It is not a de Polignac number, because 61643645 - 2¹² = 61639549 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4376 + ... + 11934.

It is an arithmetic number, because the mean of its divisors is an integer number (5307120).

Almost surely, 2^61643645 is an apocalyptic number.

It is an amenable number.

61643645 is a deficient number, since it is larger than the sum of its proper divisors (23270275).

61643645 is a wasteful number, since it uses less digits than its factorization.

61643645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7804.

The product of its digits is 51840, while the sum is 35.

The square root of 61643645 is about 7851.3466997707. The cubic root of 61643645 is about 395.0294161717.

The spelling of 61643645 in words is "sixty-one million, six hundred forty-three thousand, six hundred forty-five".