21649052437 has 2 divisors, whose sum is σ = 21649052438. Its totient is φ = 21649052436.

The previous prime is 21649052423. The next prime is 21649052449. The reversal of 21649052437 is 73425094612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20407265316 + 1241787121 = 142854^2 + 35239^2 .

It is a cyclic number.

It is not a de Polignac number, because 21649052437 - 2⁷ = 21649052309 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21649052393 and 21649052402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21649082437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10824526218 + 10824526219.

It is an arithmetic number, because the mean of its divisors is an integer number (10824526219).

Almost surely, 2^21649052437 is an apocalyptic number.

It is an amenable number.

21649052437 is a deficient number, since it is larger than the sum of its proper divisors (1).

21649052437 is an equidigital number, since it uses as much as digits as its factorization.

21649052437 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 21649052437 in words is "twenty-one billion, six hundred forty-nine million, fifty-two thousand, four hundred thirty-seven".