21403428457 has 2 divisors, whose sum is σ = 21403428458. Its totient is φ = 21403428456.

The previous prime is 21403428439. The next prime is 21403428467. The reversal of 21403428457 is 75482430412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11649100761 + 9754327696 = 107931^2 + 98764^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403428457 - 2¹⁹ = 21402904169 is a prime.

It is not a weakly prime, because it can be changed into another prime (21403428467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701714228 + 10701714229.

It is an arithmetic number, because the mean of its divisors is an integer number (10701714229).

Almost surely, 2^21403428457 is an apocalyptic number.

It is an amenable number.

21403428457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403428457 is an equidigital number, since it uses as much as digits as its factorization.

21403428457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 215040, while the sum is 40.

Adding to 21403428457 its reverse (75482430412), we get a palindrome (96885858869).

The spelling of 21403428457 in words is "twenty-one billion, four hundred three million, four hundred twenty-eight thousand, four hundred fifty-seven".