1621788836240 has 40 divisors (see below), whose sum is σ = 3771088149048. Its totient is φ = 648641710080.

The previous prime is 1621788836237. The next prime is 1621788836251. The reversal of 1621788836240 is 426388871261.

It can be written as a sum of positive squares in 4 ways, for example, as 18313667584 + 1603475168656 = 135328^2 + 1266284^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 443417 + ... + 1854776.

Almost surely, 2^{1621788836240} is an apocalyptic number.

1621788836240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621788836240 is an abundant number, since it is smaller than the sum of its proper divisors (2149299312808).

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

1621788836240 is a wasteful number, since it uses less digits than its factorization.

1621788836240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2307027 (or 2307021 counting only the distinct ones).

The product of its (nonzero) digits is 6193152, while the sum is 56.

The spelling of 1621788836240 in words is "one trillion, six hundred twenty-one billion, seven hundred eighty-eight million, eight hundred thirty-six thousand, two hundred forty".