21216362525401 has 4 divisors (see below), whose sum is σ = 21426425520804. Its totient is φ = 21006299530000.

The previous prime is 21216362525377. The next prime is 21216362525419. The reversal of 21216362525401 is 10452526361212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20052663120400 + 1163699405001 = 4478020^2 + 1078749^2 .

It is a cyclic number.

It is not a de Polignac number, because 21216362525401 - 2¹⁷ = 21216362394329 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216362525431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105031497550 + ... + 105031497751.

It is an arithmetic number, because the mean of its divisors is an integer number (5356606380201).

Almost surely, 2^{21216362525401} is an apocalyptic number.

It is an amenable number.

21216362525401 is a deficient number, since it is larger than the sum of its proper divisors (210062995403).

21216362525401 is a wasteful number, since it uses less digits than its factorization.

21216362525401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210062995402.

The product of its (nonzero) digits is 172800, while the sum is 40.

Adding to 21216362525401 its reverse (10452526361212), we get a palindrome (31668888886613).

The spelling of 21216362525401 in words is "twenty-one trillion, two hundred sixteen billion, three hundred sixty-two million, five hundred twenty-five thousand, four hundred one".