21407789297 has 2 divisors, whose sum is σ = 21407789298. Its totient is φ = 21407789296.

The previous prime is 21407789267. The next prime is 21407789311. The reversal of 21407789297 is 79298770412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19606720576 + 1801068721 = 140024^2 + 42439^2 .

It is a cyclic number.

It is not a de Polignac number, because 21407789297 - 2⁶ = 21407789233 is a prime.

It is not a weakly prime, because it can be changed into another prime (21407789267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10703894648 + 10703894649.

It is an arithmetic number, because the mean of its divisors is an integer number (10703894649).

Almost surely, 2^21407789297 is an apocalyptic number.

It is an amenable number.

21407789297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21407789297 is an equidigital number, since it uses as much as digits as its factorization.

21407789297 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3556224, while the sum is 56.

The spelling of 21407789297 in words is "twenty-one billion, four hundred seven million, seven hundred eighty-nine thousand, two hundred ninety-seven".