61220322640 has 20 divisors (see below), whose sum is σ = 142337250324. Its totient is φ = 24488129024.

The previous prime is 61220322637. The next prime is 61220322673. The reversal of 61220322640 is 4622302216.

It can be written as a sum of positive squares in 2 ways, for example, as 12310346304 + 48909976336 = 110952^2 + 221156^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 61220322599 and 61220322608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 382626937 + ... + 382627096.

Almost surely, 2^61220322640 is an apocalyptic number.

It is an amenable number.

61220322640 is an abundant number, since it is smaller than the sum of its proper divisors (81116927684).

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

61220322640 is a wasteful number, since it uses less digits than its factorization.

61220322640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765254046 (or 765254040 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

Adding to 61220322640 its reverse (4622302216), we get a palindrome (65842624856).

The spelling of 61220322640 in words is "sixty-one billion, two hundred twenty million, three hundred twenty-two thousand, six hundred forty".