1620738217980 has 144 divisors (see below), whose sum is σ = 5623362361344. Its totient is φ = 370137755520.

The previous prime is 1620738217979. The next prime is 1620738218023. The reversal of 1620738217980 is 897128370261.

It is a happy number.

1620738217980 is a `hidden beast` number, since 1 + 620 + 7 + 3 + 8 + 2 + 1 + 7 + 9 + 8 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 926229 + ... + 2024691.

Almost surely, 2^{1620738217980} is an apocalyptic number.

1620738217980 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 1620738217980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2811681180672).

1620738217980 is an abundant number, since it is smaller than the sum of its proper divisors (4002624143364).

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

1620738217980 is a wasteful number, since it uses less digits than its factorization.

1620738217980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1099656 (or 1099651 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 1620738217980 in words is "one trillion, six hundred twenty billion, seven hundred thirty-eight million, two hundred seventeen thousand, nine hundred eighty".