61561651 has 2 divisors, whose sum is σ = 61561652. Its totient is φ = 61561650.

The previous prime is 61561649. The next prime is 61561663. The reversal of 61561651 is 15616516.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61561651 - 2¹ = 61561649 is a prime.

Together with 61561649, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (61561601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30780825 + 30780826.

It is an arithmetic number, because the mean of its divisors is an integer number (30780826).

Almost surely, 2^61561651 is an apocalyptic number.

61561651 is a deficient number, since it is larger than the sum of its proper divisors (1).

61561651 is an equidigital number, since it uses as much as digits as its factorization.

61561651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5400, while the sum is 31.

The square root of 61561651 is about 7846.1233102724. The cubic root of 61561651 is about 394.8541917640.

The spelling of 61561651 in words is "sixty-one million, five hundred sixty-one thousand, six hundred fifty-one".