61505201785890 has 128 divisors (see below), whose sum is σ = 154660150759680. Its totient is φ = 15638142182400.

The previous prime is 61505201785861. The next prime is 61505201785931. The reversal of 61505201785890 is 9858710250516.

It is a self number, because there is not a number n which added to its sum of digits gives 61505201785890.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16525585 + ... + 19902395.

It is an arithmetic number, because the mean of its divisors is an integer number (1208282427810).

Almost surely, 2^{61505201785890} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61505201785890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77330075379840).

61505201785890 is an abundant number, since it is smaller than the sum of its proper divisors (93154948973790).

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

61505201785890 is a wasteful number, since it uses less digits than its factorization.

61505201785890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3377188.

The product of its (nonzero) digits is 6048000, while the sum is 57.

The spelling of 61505201785890 in words is "sixty-one trillion, five hundred five billion, two hundred one million, seven hundred eighty-five thousand, eight hundred ninety".