21213545065401 has 64 divisors (see below), whose sum is σ = 31029567206400. Its totient is φ = 12812097957120.

The previous prime is 21213545065387. The next prime is 21213545065417. The reversal of 21213545065401 is 10456054531212.

It is not a de Polignac number, because 21213545065401 - 2¹⁰ = 21213545064377 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 21213545065401.

It is not an unprimeable number, because it can be changed into a prime (21213545065001) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1170006106 + ... + 1170024236.

It is an arithmetic number, because the mean of its divisors is an integer number (484836987600).

Almost surely, 2^{21213545065401} is an apocalyptic number.

It is an amenable number.

21213545065401 is a deficient number, since it is larger than the sum of its proper divisors (9816022140999).

21213545065401 is a wasteful number, since it uses less digits than its factorization.

21213545065401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19846.

The product of its (nonzero) digits is 144000, while the sum is 39.

Adding to 21213545065401 its reverse (10456054531212), we get a palindrome (31669599596613).

The spelling of 21213545065401 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-five million, sixty-five thousand, four hundred one".