1631121321680 has 40 divisors (see below), whose sum is σ = 4015436904072. Its totient is φ = 614069202944.

The previous prime is 1631121321667. The next prime is 1631121321689. The reversal of 1631121321680 is 861231211361.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 456602924176 + 1174518397504 = 675724^2 + 1083752^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1631121321680² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1631121321680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631121321689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 599675597 + ... + 599678316.

Almost surely, 2^{1631121321680} is an apocalyptic number.

1631121321680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1631121321680 is an abundant number, since it is smaller than the sum of its proper divisors (2384315582392).

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

1631121321680 is a wasteful number, since it uses less digits than its factorization.

1631121321680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1199353943 (or 1199353937 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The spelling of 1631121321680 in words is "one trillion, six hundred thirty-one billion, one hundred twenty-one million, three hundred twenty-one thousand, six hundred eighty".