61521220331 has 8 divisors (see below), whose sum is σ = 62523080928. Its totient is φ = 60523120000.

The previous prime is 61521220309. The next prime is 61521220349. The reversal of 61521220331 is 13302212516.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61521220331 is a prime.

It is a super-2 number, since 2×61521220331² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61521220331.

It is not an unprimeable number, because it can be changed into a prime (61521220381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 907070 + ... + 972531.

It is an arithmetic number, because the mean of its divisors is an integer number (7815385116).

Almost surely, 2^61521220331 is an apocalyptic number.

61521220331 is a deficient number, since it is larger than the sum of its proper divisors (1001860597).

61521220331 is a wasteful number, since it uses less digits than its factorization.

61521220331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1880133.

The product of its (nonzero) digits is 2160, while the sum is 26.

Adding to 61521220331 its reverse (13302212516), we get a palindrome (74823432847).

The spelling of 61521220331 in words is "sixty-one billion, five hundred twenty-one million, two hundred twenty thousand, three hundred thirty-one".