21661225466057 has 2 divisors, whose sum is σ = 21661225466058. Its totient is φ = 21661225466056.

The previous prime is 21661225466003. The next prime is 21661225466149. The reversal of 21661225466057 is 75066452216612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21657677595961 + 3547870096 = 4653781^2 + 59564^2 .

It is a cyclic number.

It is not a de Polignac number, because 21661225466057 - 2¹² = 21661225461961 is a prime.

It is not a weakly prime, because it can be changed into another prime (21661225436057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830612733028 + 10830612733029.

It is an arithmetic number, because the mean of its divisors is an integer number (10830612733029).

Almost surely, 2^{21661225466057} is an apocalyptic number.

It is an amenable number.

21661225466057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21661225466057 is an equidigital number, since it uses as much as digits as its factorization.

21661225466057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7257600, while the sum is 53.

The spelling of 21661225466057 in words is "twenty-one trillion, six hundred sixty-one billion, two hundred twenty-five million, four hundred sixty-six thousand, fifty-seven".