61561637 has 4 divisors (see below), whose sum is σ = 61632396. Its totient is φ = 61490880.

The previous prime is 61561631. The next prime is 61561649. The reversal of 61561637 is 73616516.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4800481 + 56761156 = 2191^2 + 7534^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61561637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61561597 and 61561606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34058 + ... + 35819.

It is an arithmetic number, because the mean of its divisors is an integer number (15408099).

Almost surely, 2^61561637 is an apocalyptic number.

It is an amenable number.

61561637 is a deficient number, since it is larger than the sum of its proper divisors (70759).

61561637 is an equidigital number, since it uses as much as digits as its factorization.

61561637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70758.

The product of its digits is 22680, while the sum is 35.

The square root of 61561637 is about 7846.1224181120. The cubic root of 61561637 is about 394.8541618322.

The spelling of 61561637 in words is "sixty-one million, five hundred sixty-one thousand, six hundred thirty-seven".