221421255546649 has 2 divisors, whose sum is σ = 221421255546650. Its totient is φ = 221421255546648.

The previous prime is 221421255546643. The next prime is 221421255546679. The reversal of 221421255546649 is 946645552124122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214503997862025 + 6917257684624 = 14645955^2 + 2630068^2 .

It is a cyclic number.

It is not a de Polignac number, because 221421255546649 - 2³ = 221421255546641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221421255546593 and 221421255546602.

It is not a weakly prime, because it can be changed into another prime (221421255546641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110710627773324 + 110710627773325.

It is an arithmetic number, because the mean of its divisors is an integer number (110710627773325).

Almost surely, 2^{221421255546649} is an apocalyptic number.

It is an amenable number.

221421255546649 is a deficient number, since it is larger than the sum of its proper divisors (1).

221421255546649 is an equidigital number, since it uses as much as digits as its factorization.

221421255546649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472000, while the sum is 58.

The spelling of 221421255546649 in words is "two hundred twenty-one trillion, four hundred twenty-one billion, two hundred fifty-five million, five hundred forty-six thousand, six hundred forty-nine".