21434020849 has 2 divisors, whose sum is σ = 21434020850. Its totient is φ = 21434020848.

The previous prime is 21434020831. The next prime is 21434020921. The reversal of 21434020849 is 94802043412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18994352400 + 2439668449 = 137820^2 + 49393^2 .

It is a cyclic number.

It is not a de Polignac number, because 21434020849 - 2⁷ = 21434020721 is a prime.

It is not a weakly prime, because it can be changed into another prime (21434029849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717010424 + 10717010425.

It is an arithmetic number, because the mean of its divisors is an integer number (10717010425).

Almost surely, 2^21434020849 is an apocalyptic number.

It is an amenable number.

21434020849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21434020849 is an equidigital number, since it uses as much as digits as its factorization.

21434020849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 37.

The spelling of 21434020849 in words is "twenty-one billion, four hundred thirty-four million, twenty thousand, eight hundred forty-nine".