1550661840 has 800 divisors, whose sum is σ = 7002051840. Its totient is φ = 312947712.

The previous prime is 1550661811. The next prime is 1550661941. The reversal of 1550661840 is 481660551.

1550661840 is a `hidden beast` number, since 1 + 550 + 6 + 61 + 8 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1550661795 and 1550661804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 67420069 + ... + 67420091.

Almost surely, 2^1550661840 is an apocalyptic number.

1550661840 is a gapful number since it is divisible by the number (10) 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 1550661840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3501025920).

1550661840 is an abundant number, since it is smaller than the sum of its proper divisors (5451390000).

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

1550661840 is a wasteful number, since it uses less digits than its factorization.

1550661840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1550661840 is about 39378.4438493956. The cubic root of 1550661840 is about 1157.4592229227.

The spelling of 1550661840 in words is "one billion, five hundred fifty million, six hundred sixty-one thousand, eight hundred forty".