61909639 has 8 divisors (see below), whose sum is σ = 67781520. Its totient is φ = 56078400.

The previous prime is 61909609. The next prime is 61909643. The reversal of 61909639 is 93690916.

61909639 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61909639 - 2¹³ = 61901447 is a prime.

It is a super-2 number, since 2×61909639² = 7665606802220642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61909595 and 61909604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61909609) 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 7 ways as a sum of consecutive naturals, for example, 6924 + ... + 13105.

It is an arithmetic number, because the mean of its divisors is an integer number (8472690).

Almost surely, 2^61909639 is an apocalyptic number.

61909639 is a deficient number, since it is larger than the sum of its proper divisors (5871881).

61909639 is a wasteful number, since it uses less digits than its factorization.

61909639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20321.

The product of its (nonzero) digits is 78732, while the sum is 43.

The square root of 61909639 is about 7868.2678525836. The cubic root of 61909639 is about 395.5967884251.

The spelling of 61909639 in words is "sixty-one million, nine hundred nine thousand, six hundred thirty-nine".