61204721 has 4 divisors (see below), whose sum is σ = 61261812. Its totient is φ = 61147632.

The previous prime is 61204711. The next prime is 61204727. The reversal of 61204721 is 12740216.

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 47059600 + 14145121 = 6860^2 + 3761^2 .

It is a cyclic number.

It is not a de Polignac number, because 61204721 - 2¹⁰ = 61203697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61204727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26906 + ... + 29091.

It is an arithmetic number, because the mean of its divisors is an integer number (15315453).

Almost surely, 2^61204721 is an apocalyptic number.

It is an amenable number.

61204721 is a deficient number, since it is larger than the sum of its proper divisors (57091).

61204721 is a wasteful number, since it uses less digits than its factorization.

61204721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57090.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 61204721 is about 7823.3446172337. The cubic root of 61204721 is about 394.0896001571.

Adding to 61204721 its reverse (12740216), we get a palindrome (73944937).

The spelling of 61204721 in words is "sixty-one million, two hundred four thousand, seven hundred twenty-one".