61133323721 has 4 divisors (see below), whose sum is σ = 61139384832. Its totient is φ = 61127262612.

The previous prime is 61133323697. The next prime is 61133323723. The reversal of 61133323721 is 12732333116.

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 61133323721 - 2³⁴ = 43953454537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61133323723) 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, 3015401 + ... + 3035606.

It is an arithmetic number, because the mean of its divisors is an integer number (15284846208).

Almost surely, 2^61133323721 is an apocalyptic number.

It is an amenable number.

61133323721 is a deficient number, since it is larger than the sum of its proper divisors (6061111).

61133323721 is a wasteful number, since it uses less digits than its factorization.

61133323721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6061110.

The product of its digits is 13608, while the sum is 32.

Adding to 61133323721 its reverse (12732333116), we get a palindrome (73865656837).

The spelling of 61133323721 in words is "sixty-one billion, one hundred thirty-three million, three hundred twenty-three thousand, seven hundred twenty-one".