61221081600 has 1080 divisors, whose sum is σ = 262005194880. Its totient is φ = 13370572800.

The previous prime is 61221081589. The next prime is 61221081617. The reversal of 61221081600 is 618012216.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 774950361 + ... + 774950439.

Almost surely, 2^61221081600 is an apocalyptic number.

61221081600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61221081600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131002597440).

61221081600 is an abundant number, since it is smaller than the sum of its proper divisors (200784113280).

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

61221081600 is a wasteful number, since it uses less digits than its factorization.

61221081600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

Adding to 61221081600 its reverse (618012216), we get a palindrome (61839093816).

The spelling of 61221081600 in words is "sixty-one billion, two hundred twenty-one million, eighty-one thousand, six hundred".