61809889 has 2 divisors, whose sum is σ = 61809890. Its totient is φ = 61809888.

The previous prime is 61809863. The next prime is 61809893. The reversal of 61809889 is 98890816.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52707600 + 9102289 = 7260^2 + 3017^2 .

It is a cyclic number.

It is not a de Polignac number, because 61809889 - 2¹⁷ = 61678817 is a prime.

It is not a weakly prime, because it can be changed into another prime (61809899) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30904944 + 30904945.

It is an arithmetic number, because the mean of its divisors is an integer number (30904945).

Almost surely, 2^61809889 is an apocalyptic number.

It is an amenable number.

61809889 is a deficient number, since it is larger than the sum of its proper divisors (1).

61809889 is an equidigital number, since it uses as much as digits as its factorization.

61809889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 248832, while the sum is 49.

The square root of 61809889 is about 7861.9265450651. The cubic root of 61809889 is about 395.3842098316.

The spelling of 61809889 in words is "sixty-one million, eight hundred nine thousand, eight hundred eighty-nine".