1621155651980 has 24 divisors (see below), whose sum is σ = 3447520883520. Its totient is φ = 640253877120.

The previous prime is 1621155651961. The next prime is 1621155652031. The reversal of 1621155651980 is 891565511261.

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, 513022361 + ... + 513025520.

It is an arithmetic number, because the mean of its divisors is an integer number (143646703480).

Almost surely, 2^{1621155651980} is an apocalyptic number.

1621155651980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1621155651980 is an abundant number, since it is smaller than the sum of its proper divisors (1826365231540).

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

1621155651980 is a wasteful number, since it uses less digits than its factorization.

1621155651980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026047969 (or 1026047967 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 50.

The spelling of 1621155651980 in words is "one trillion, six hundred twenty-one billion, one hundred fifty-five million, six hundred fifty-one thousand, nine hundred eighty".