61161721 has 4 divisors (see below), whose sum is σ = 61936000. Its totient is φ = 60387444.

The previous prime is 61161713. The next prime is 61161739. The reversal of 61161721 is 12716116.

It is a happy number.

61161721 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 61161721 - 2³ = 61161713 is a prime.

It is a super-2 number, since 2×61161721² = 7481512231363682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61101721) 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, 387021 + ... + 387178.

It is an arithmetic number, because the mean of its divisors is an integer number (15484000).

Almost surely, 2^61161721 is an apocalyptic number.

It is an amenable number.

61161721 is a deficient number, since it is larger than the sum of its proper divisors (774279).

61161721 is an equidigital number, since it uses as much as digits as its factorization.

61161721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 774278.

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

The square root of 61161721 is about 7820.5959491589. The cubic root of 61161721 is about 393.9972879815.

Adding to 61161721 its reverse (12716116), we get a palindrome (73877837).

The spelling of 61161721 in words is "sixty-one million, one hundred sixty-one thousand, seven hundred twenty-one".