21624154655261 has 2 divisors, whose sum is σ = 21624154655262. Its totient is φ = 21624154655260.

The previous prime is 21624154655251. The next prime is 21624154655269. The reversal of 21624154655261 is 16255645142612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21615014148025 + 9140507236 = 4649195^2 + 95606^2 .

It is a cyclic number.

It is not a de Polignac number, because 21624154655261 - 2¹⁰ = 21624154654237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21624154655269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10812077327630 + 10812077327631.

It is an arithmetic number, because the mean of its divisors is an integer number (10812077327631).

Almost surely, 2^{21624154655261} is an apocalyptic number.

It is an amenable number.

21624154655261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21624154655261 is an equidigital number, since it uses as much as digits as its factorization.

21624154655261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456000, while the sum is 50.

Adding to 21624154655261 its reverse (16255645142612), we get a palindrome (37879799797873).

The spelling of 21624154655261 in words is "twenty-one trillion, six hundred twenty-four billion, one hundred fifty-four million, six hundred fifty-five thousand, two hundred sixty-one".