61521220263 has 4 divisors (see below), whose sum is σ = 82028293688. Its totient is φ = 41014146840.

The previous prime is 61521220231. The next prime is 61521220307. The reversal of 61521220263 is 36202212516.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 61521220263 - 2⁵ = 61521220231 is a prime.

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 61521220263.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61521221263) 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, 10253536708 + ... + 10253536713.

It is an arithmetic number, because the mean of its divisors is an integer number (20507073422).

Almost surely, 2^61521220263 is an apocalyptic number.

61521220263 is a deficient number, since it is larger than the sum of its proper divisors (20507073425).

61521220263 is a wasteful number, since it uses less digits than its factorization.

61521220263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20507073424.

The product of its (nonzero) digits is 8640, while the sum is 30.

Adding to 61521220263 its reverse (36202212516), we get a palindrome (97723432779).

The spelling of 61521220263 in words is "sixty-one billion, five hundred twenty-one million, two hundred twenty thousand, two hundred sixty-three".