21457264237 has 2 divisors, whose sum is σ = 21457264238. Its totient is φ = 21457264236.

The previous prime is 21457264223. The next prime is 21457264253. The reversal of 21457264237 is 73246275412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14014061161 + 7443203076 = 118381^2 + 86274^2 .

It is a cyclic number.

It is not a de Polignac number, because 21457264237 - 2¹⁹ = 21456739949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21457264193 and 21457264202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21457264207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10728632118 + 10728632119.

It is an arithmetic number, because the mean of its divisors is an integer number (10728632119).

Almost surely, 2^21457264237 is an apocalyptic number.

It is an amenable number.

21457264237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21457264237 is an equidigital number, since it uses as much as digits as its factorization.

21457264237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 564480, while the sum is 43.

The spelling of 21457264237 in words is "twenty-one billion, four hundred fifty-seven million, two hundred sixty-four thousand, two hundred thirty-seven".