61551512020 has 12 divisors (see below), whose sum is σ = 129258175284. Its totient is φ = 24620604800.

The previous prime is 61551511993. The next prime is 61551512021. The reversal of 61551512020 is 2021515516.

It can be written as a sum of positive squares in 2 ways, for example, as 46550651536 + 15000860484 = 215756^2 + 122478^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 61551512020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61551512021) 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, 1538787781 + ... + 1538787820.

It is an arithmetic number, because the mean of its divisors is an integer number (10771514607).

Almost surely, 2^61551512020 is an apocalyptic number.

It is an amenable number.

61551512020 is an abundant number, since it is smaller than the sum of its proper divisors (67706663264).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61551512020 is a wasteful number, since it uses less digits than its factorization.

61551512020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3077575610 (or 3077575608 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 28.

The spelling of 61551512020 in words is "sixty-one billion, five hundred fifty-one million, five hundred twelve thousand, twenty".