21602811655811 has 2 divisors, whose sum is σ = 21602811655812. Its totient is φ = 21602811655810.

The previous prime is 21602811655807. The next prime is 21602811655837. The reversal of 21602811655811 is 11855611820612.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21602811655811 - 2² = 21602811655807 is a prime.

It is not a weakly prime, because it can be changed into another prime (21602811655861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801405827905 + 10801405827906.

It is an arithmetic number, because the mean of its divisors is an integer number (10801405827906).

Almost surely, 2^{21602811655811} is an apocalyptic number.

21602811655811 is a deficient number, since it is larger than the sum of its proper divisors (1).

21602811655811 is an equidigital number, since it uses as much as digits as its factorization.

21602811655811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 230400, while the sum is 47.

The spelling of 21602811655811 in words is "twenty-one trillion, six hundred two billion, eight hundred eleven million, six hundred fifty-five thousand, eight hundred eleven".