61721520121223 has 16 divisors (see below), whose sum is σ = 61846336373760. Its totient is φ = 61596863040000.

The previous prime is 61721520121201. The next prime is 61721520121273. The reversal of 61721520121223 is 32212102512716.

It is a cyclic number.

It is not a de Polignac number, because 61721520121223 - 2²⁸ = 61721251685767 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 (61721520121273) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6409956773 + ... + 6409966401.

It is an arithmetic number, because the mean of its divisors is an integer number (3865396023360).

Almost surely, 2^{61721520121223} is an apocalyptic number.

61721520121223 is a deficient number, since it is larger than the sum of its proper divisors (124816252537).

61721520121223 is a wasteful number, since it uses less digits than its factorization.

61721520121223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16618.

The product of its (nonzero) digits is 20160, while the sum is 35.

Adding to 61721520121223 its reverse (32212102512716), we get a palindrome (93933622633939).

The spelling of 61721520121223 in words is "sixty-one trillion, seven hundred twenty-one billion, five hundred twenty million, one hundred twenty-one thousand, two hundred twenty-three".