61699909 has 2 divisors, whose sum is σ = 61699910. Its totient is φ = 61699908.

The previous prime is 61699903. The next prime is 61699927. The reversal of 61699909 is 90999616.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52519009 + 9180900 = 7247^2 + 3030^2 .

It is a cyclic number.

It is not a de Polignac number, because 61699909 - 2⁵ = 61699877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61699903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30849954 + 30849955.

It is an arithmetic number, because the mean of its divisors is an integer number (30849955).

Almost surely, 2^61699909 is an apocalyptic number.

It is an amenable number.

61699909 is a deficient number, since it is larger than the sum of its proper divisors (1).

61699909 is an equidigital number, since it uses as much as digits as its factorization.

61699909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 236196, while the sum is 49.

The square root of 61699909 is about 7854.9289621231. The cubic root of 61699909 is about 395.1495646823.

The spelling of 61699909 in words is "sixty-one million, six hundred ninety-nine thousand, nine hundred nine".