61644333328550 has 72 divisors (see below), whose sum is σ = 133392356405280. Its totient is φ = 21132958123200.

The previous prime is 61644333328549. The next prime is 61644333328553. The reversal of 61644333328550 is 5582333344616.

It is a junction number, because it is equal to n+sod(n) for n = 61644333328492 and 61644333328501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61644333328553) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21849731 + ... + 24509169.

It is an arithmetic number, because the mean of its divisors is an integer number (1852671616740).

Almost surely, 2^{61644333328550} is an apocalyptic number.

61644333328550 is an abundant number, since it is smaller than the sum of its proper divisors (71748023076730).

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

61644333328550 is a wasteful number, since it uses less digits than its factorization.

61644333328550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2668926 (or 2668914 counting only the distinct ones).

The product of its (nonzero) digits is 18662400, while the sum is 53.

The spelling of 61644333328550 in words is "sixty-one trillion, six hundred forty-four billion, three hundred thirty-three million, three hundred twenty-eight thousand, five hundred fifty".