61721611 has 24 divisors (see below), whose sum is σ = 76485600. Its totient is φ = 48619776.

The previous prime is 61721603. The next prime is 61721623. The reversal of 61721611 is 11612716.

It is a happy number.

It is not a de Polignac number, because 61721611 - 2³ = 61721603 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 (61721711) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 414165 + ... + 414313.

It is an arithmetic number, because the mean of its divisors is an integer number (3186900).

Almost surely, 2^61721611 is an apocalyptic number.

61721611 is a deficient number, since it is larger than the sum of its proper divisors (14763989).

61721611 is a wasteful number, since it uses less digits than its factorization.

61721611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 232 counting only the distinct ones).

The product of its digits is 504, while the sum is 25.

The square root of 61721611 is about 7856.3102662764. The cubic root of 61721611 is about 395.1958885249.

The spelling of 61721611 in words is "sixty-one million, seven hundred twenty-one thousand, six hundred eleven".