21620551613417 has 2 divisors, whose sum is σ = 21620551613418. Its totient is φ = 21620551613416.

The previous prime is 21620551613407. The next prime is 21620551613449. The reversal of 21620551613417 is 71431615502612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20655243398416 + 965308215001 = 4544804^2 + 982501^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620551613417 - 2⁸ = 21620551613161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21620551613407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810275806708 + 10810275806709.

It is an arithmetic number, because the mean of its divisors is an integer number (10810275806709).

Almost surely, 2^{21620551613417} is an apocalyptic number.

It is an amenable number.

21620551613417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620551613417 is an equidigital number, since it uses as much as digits as its factorization.

21620551613417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 302400, while the sum is 44.

The spelling of 21620551613417 in words is "twenty-one trillion, six hundred twenty billion, five hundred fifty-one million, six hundred thirteen thousand, four hundred seventeen".