61399729 has 4 divisors (see below), whose sum is σ = 61417984. Its totient is φ = 61381476.

The previous prime is 61399727. The next prime is 61399799. The reversal of 61399729 is 92799316.

61399729 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61399729 - 2¹ = 61399727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61399727) 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, 2457 + ... + 11350.

It is an arithmetic number, because the mean of its divisors is an integer number (15354496).

Almost surely, 2^61399729 is an apocalyptic number.

It is an amenable number.

61399729 is a deficient number, since it is larger than the sum of its proper divisors (18255).

61399729 is a wasteful number, since it uses less digits than its factorization.

61399729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18254.

The product of its digits is 183708, while the sum is 46.

The square root of 61399729 is about 7835.7979172513. The cubic root of 61399729 is about 394.5077005270.

It can be divided in two parts, 61399 and 729, that added together give a triangular number (62128 = T₃₅₂).

The spelling of 61399729 in words is "sixty-one million, three hundred ninety-nine thousand, seven hundred twenty-nine".