21221653154645 has 8 divisors (see below), whose sum is σ = 25489325665440. Its totient is φ = 16961761270480.

The previous prime is 21221653154641. The next prime is 21221653154659. The reversal of 21221653154645 is 54645135612212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21221653154645 - 2² = 21221653154641 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221653154645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221653154641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1945150655 + ... + 1945161564.

It is an arithmetic number, because the mean of its divisors is an integer number (3186165708180).

Almost surely, 2^{21221653154645} is an apocalyptic number.

It is an amenable number.

21221653154645 is a deficient number, since it is larger than the sum of its proper divisors (4267672510795).

21221653154645 is a wasteful number, since it uses less digits than its factorization.

21221653154645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3890313315.

The product of its digits is 1728000, while the sum is 47.

Adding to 21221653154645 its reverse (54645135612212), we get a palindrome (75866788766857).

The spelling of 21221653154645 in words is "twenty-one trillion, two hundred twenty-one billion, six hundred fifty-three million, one hundred fifty-four thousand, six hundred forty-five".