61720231 has 2 divisors, whose sum is σ = 61720232. Its totient is φ = 61720230.

The previous prime is 61720213. The next prime is 61720237. The reversal of 61720231 is 13202716.

Together with previous prime (61720213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61720231 - 2¹⁹ = 61195943 is a prime.

It is a super-2 number, since 2×61720231² = 7618773829386722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61720237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30860115 + 30860116.

It is an arithmetic number, because the mean of its divisors is an integer number (30860116).

Almost surely, 2^61720231 is an apocalyptic number.

61720231 is a deficient number, since it is larger than the sum of its proper divisors (1).

61720231 is an equidigital number, since it uses as much as digits as its factorization.

61720231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 61720231 is about 7856.2224382969. Note that the first 3 decimals coincide. The cubic root of 61720231 is about 395.1929431795.

Adding to 61720231 its reverse (13202716), we get a palindrome (74922947).

The spelling of 61720231 in words is "sixty-one million, seven hundred twenty thousand, two hundred thirty-one".