61813 has 2 divisors, whose sum is σ = 61814. Its totient is φ = 61812.

The previous prime is 61781. The next prime is 61819. The reversal of 61813 is 31816.

It is the 102-nd star number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58564 + 3249 = 242^2 + 57^2 .

It is a cyclic number.

It is not a de Polignac number, because 61813 - 2⁵ = 61781 is a prime.

61813 is a lucky number.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30906 + 30907.

It is an arithmetic number, because the mean of its divisors is an integer number (30907).

2⁶¹⁸¹³ is an apocalyptic number.

It is an amenable number.

61813 is a deficient number, since it is larger than the sum of its proper divisors (1).

61813 is an equidigital number, since it uses as much as digits as its factorization.

61813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 19.

The square root of 61813 is about 248.6222033528. The cubic root of 61813 is about 39.5390843180.

It can be divided in two parts, 6 and 1813, that multiplied together give a triangular number (10878 = T₁₄₇).

The spelling of 61813 in words is "sixty-one thousand, eight hundred thirteen".