21401616605357 has 2 divisors, whose sum is σ = 21401616605358. Its totient is φ = 21401616605356.

The previous prime is 21401616605321. The next prime is 21401616605407. The reversal of 21401616605357 is 75350661610412.

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., 19218701959396 + 2182914645961 = 4383914^2 + 1477469^2 .

It is a cyclic number.

It is not a de Polignac number, because 21401616605357 - 2¹⁸ = 21401616343213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21401616605657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700808302678 + 10700808302679.

It is an arithmetic number, because the mean of its divisors is an integer number (10700808302679).

Almost surely, 2^{21401616605357} is an apocalyptic number.

It is an amenable number.

21401616605357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21401616605357 is an equidigital number, since it uses as much as digits as its factorization.

21401616605357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 47.

The spelling of 21401616605357 in words is "twenty-one trillion, four hundred one billion, six hundred sixteen million, six hundred five thousand, three hundred fifty-seven".