21816379801969 has 2 divisors, whose sum is σ = 21816379801970. Its totient is φ = 21816379801968.

The previous prime is 21816379801933. The next prime is 21816379802027. The reversal of 21816379801969 is 96910897361812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20368477791025 + 1447902010944 = 4513145^2 + 1203288^2 .

It is a cyclic number.

It is not a de Polignac number, because 21816379801969 - 2¹³ = 21816379793777 is a prime.

It is a super-2 number, since 2×21816379801969² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21816379801898 and 21816379801907.

It is not a weakly prime, because it can be changed into another prime (21816379807969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10908189900984 + 10908189900985.

It is an arithmetic number, because the mean of its divisors is an integer number (10908189900985).

Almost surely, 2^{21816379801969} is an apocalyptic number.

It is an amenable number.

21816379801969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21816379801969 is an equidigital number, since it uses as much as digits as its factorization.

21816379801969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70543872, while the sum is 70.

The spelling of 21816379801969 in words is "twenty-one trillion, eight hundred sixteen billion, three hundred seventy-nine million, eight hundred one thousand, nine hundred sixty-nine".