2661361920 has 720 divisors, whose sum is σ = 11515405440. Its totient is φ = 573308928.

The previous prime is 2661361907. The next prime is 2661361979. The reversal of 2661361920 is 291631662.

It is a happy number.

2661361920 is a `hidden beast` number, since 2 + 6 + 6 + 13 + 619 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 13789344 + ... + 13789536.

Almost surely, 2^2661361920 is an apocalyptic number.

2661361920 is a gapful number since it is divisible by the number (20) 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 2661361920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5757702720).

2661361920 is an abundant number, since it is smaller than the sum of its proper divisors (8854043520).

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

2661361920 is a wasteful number, since it uses less digits than its factorization.

2661361920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 229 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 2661361920 is about 51588.3893914125. The cubic root of 2661361920 is about 1385.8024118174.

2661361920 divided by its sum of digits (36) gives a triangular number (73926720 = T₁₂₁₅₉).

The spelling of 2661361920 in words is "two billion, six hundred sixty-one million, three hundred sixty-one thousand, nine hundred twenty".