21820199441 has 2 divisors, whose sum is σ = 21820199442. Its totient is φ = 21820199440.

The previous prime is 21820199437. The next prime is 21820199519. The reversal of 21820199441 is 14499102812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20078890000 + 1741309441 = 141700^2 + 41729^2 .

It is a cyclic number.

It is not a de Polignac number, because 21820199441 - 2² = 21820199437 is a prime.

It is a super-2 number, since 2×21820199441² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21820199341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910099720 + 10910099721.

It is an arithmetic number, because the mean of its divisors is an integer number (10910099721).

Almost surely, 2^21820199441 is an apocalyptic number.

It is an amenable number.

21820199441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21820199441 is an equidigital number, since it uses as much as digits as its factorization.

21820199441 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 41.

The spelling of 21820199441 in words is "twenty-one billion, eight hundred twenty million, one hundred ninety-nine thousand, four hundred forty-one".