21661353004619 has 2 divisors, whose sum is σ = 21661353004620. Its totient is φ = 21661353004618.

The previous prime is 21661353004553. The next prime is 21661353004667. The reversal of 21661353004619 is 91640035316612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21661353004619 - 2²⁴ = 21661336227403 is a prime.

It is a super-2 number, since 2×21661353004619² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21661353004679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830676502309 + 10830676502310.

It is an arithmetic number, because the mean of its divisors is an integer number (10830676502310).

Almost surely, 2^{21661353004619} is an apocalyptic number.

21661353004619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21661353004619 is an equidigital number, since it uses as much as digits as its factorization.

21661353004619 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 699840, while the sum is 47.

The spelling of 21661353004619 in words is "twenty-one trillion, six hundred sixty-one billion, three hundred fifty-three million, four thousand, six hundred nineteen".