61213909 has 4 divisors (see below), whose sum is σ = 61441740. Its totient is φ = 60986080.

The previous prime is 61213903. The next prime is 61213921. The reversal of 61213909 is 90931216.

61213909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 32890225 + 28323684 = 5735^2 + 5322^2 .

It is a cyclic number.

It is not a de Polignac number, because 61213909 - 2¹¹ = 61211861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61213903) 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 3 ways as a sum of consecutive naturals, for example, 113512 + ... + 114049.

It is an arithmetic number, because the mean of its divisors is an integer number (15360435).

Almost surely, 2^61213909 is an apocalyptic number.

It is an amenable number.

61213909 is a deficient number, since it is larger than the sum of its proper divisors (227831).

61213909 is a wasteful number, since it uses less digits than its factorization.

61213909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227830.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 61213909 is about 7823.9318120751. The cubic root of 61213909 is about 394.1093193008.

The spelling of 61213909 in words is "sixty-one million, two hundred thirteen thousand, nine hundred nine".