61216391 has 4 divisors (see below), whose sum is σ = 62640072. Its totient is φ = 59792712.

The previous prime is 61216373. The next prime is 61216417. The reversal of 61216391 is 19361216.

61216391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 61216391 - 2¹⁸ = 60954247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61216591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 711776 + ... + 711861.

It is an arithmetic number, because the mean of its divisors is an integer number (15660018).

Almost surely, 2^61216391 is an apocalyptic number.

61216391 is a deficient number, since it is larger than the sum of its proper divisors (1423681).

61216391 is a wasteful number, since it uses less digits than its factorization.

61216391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1423680.

The product of its digits is 1944, while the sum is 29.

The square root of 61216391 is about 7824.0904263691. The cubic root of 61216391 is about 394.1146457924.

The spelling of 61216391 in words is "sixty-one million, two hundred sixteen thousand, three hundred ninety-one".