1621280343553 has 16 divisors (see below), whose sum is σ = 1749287927296. Its totient is φ = 1493745960960.

The previous prime is 1621280343523. The next prime is 1621280343587. The reversal of 1621280343553 is 3553430821261.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1621280343553 - 2⁵ = 1621280343521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1621280343523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14799526 + ... + 14908672.

It is an arithmetic number, because the mean of its divisors is an integer number (109330495456).

Almost surely, 2^{1621280343553} is an apocalyptic number.

1621280343553 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1621280343553 is a deficient number, since it is larger than the sum of its proper divisors (128007583743).

1621280343553 is a wasteful number, since it uses less digits than its factorization.

1621280343553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111304.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 1621280343553 in words is "one trillion, six hundred twenty-one billion, two hundred eighty million, three hundred forty-three thousand, five hundred fifty-three".