61520191 has 2 divisors, whose sum is σ = 61520192.
Its totient is φ = 61520190.
The previous prime is 61520189. The next prime is 61520203. The reversal of 61520191 is 19102516.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 61520191 - 21 = 61520189 is a prime.
Together with 61520189, it forms a pair of twin primes.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (61520491) by changing a digit.
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 as a sum of consecutive naturals, namely, 30760095 + 30760096.
It is an arithmetic number, because the mean of its divisors is an integer number (30760096).
Almost surely, 261520191 is an apocalyptic number.
61520191 is a deficient number, since it is larger than the sum of its proper divisors (1).
61520191 is an equidigital number, since it uses as much as digits as its factorization.
61520191 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 540, while the sum is 25.
The square root of 61520191 is about 7843.4807961772.
The cubic root of 61520191 is about 394.7655308799.
The spelling of 61520191 in words is "sixty-one million, five hundred twenty thousand, one hundred ninety-one".