2121403653645 has 16 divisors (see below), whose sum is σ = 3413865768192. Its totient is φ = 1124875307840.

The previous prime is 2121403653637. The next prime is 2121403653659. The reversal of 2121403653645 is 5463563041212.

It is not a de Polignac number, because 2121403653645 - 2³ = 2121403653637 is a prime.

It is a super-3 number, since 3×2121403653645³ (a number of 38 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2121403653597 and 2121403653606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 408745701 + ... + 408750890.

It is an arithmetic number, because the mean of its divisors is an integer number (213366610512).

Almost surely, 2^{2121403653645} is an apocalyptic number.

It is an amenable number.

2121403653645 is a deficient number, since it is larger than the sum of its proper divisors (1292462114547).

2121403653645 is a wasteful number, since it uses less digits than its factorization.

2121403653645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817496772.

The product of its (nonzero) digits is 518400, while the sum is 42.

Adding to 2121403653645 its reverse (5463563041212), we get a palindrome (7584966694857).

The spelling of 2121403653645 in words is "two trillion, one hundred twenty-one billion, four hundred three million, six hundred fifty-three thousand, six hundred forty-five".