1551818761920 has 1344 divisors, whose sum is σ = 6703873612800. Its totient is φ = 333773291520.

The previous prime is 1551818761859. The next prime is 1551818761943. The reversal of 1551818761920 is 291678181551.

1551818761920 is a `hidden beast` number, since 1 + 5 + 5 + 1 + 8 + 18 + 7 + 619 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1871916066 + ... + 1871916894.

It is an arithmetic number, because the mean of its divisors is an integer number (4988001200).

Almost surely, 2^{1551818761920} is an apocalyptic number.

1551818761920 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 1551818761920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3351936806400).

1551818761920 is an abundant number, since it is smaller than the sum of its proper divisors (5152054850880).

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

1551818761920 is a wasteful number, since it uses less digits than its factorization.

1551818761920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068 (or 1046 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 54.

The spelling of 1551818761920 in words is "one trillion, five hundred fifty-one billion, eight hundred eighteen million, seven hundred sixty-one thousand, nine hundred twenty".