21054905721611 has 2 divisors, whose sum is σ = 21054905721612. Its totient is φ = 21054905721610.

The previous prime is 21054905721589. The next prime is 21054905721617. The reversal of 21054905721611 is 11612750945012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21054905721611 - 2³⁴ = 21037725852427 is a prime.

It is not a weakly prime, because it can be changed into another prime (21054905721617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527452860805 + 10527452860806.

It is an arithmetic number, because the mean of its divisors is an integer number (10527452860806).

Almost surely, 2^{21054905721611} is an apocalyptic number.

21054905721611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054905721611 is an equidigital number, since it uses as much as digits as its factorization.

21054905721611 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 44.

The spelling of 21054905721611 in words is "twenty-one trillion, fifty-four billion, nine hundred five million, seven hundred twenty-one thousand, six hundred eleven".