21421342973 has 2 divisors, whose sum is σ = 21421342974. Its totient is φ = 21421342972.

The previous prime is 21421342967. The next prime is 21421343023. The reversal of 21421342973 is 37924312412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19587961849 + 1833381124 = 139957^2 + 42818^2 .

It is a cyclic number.

It is not a de Polignac number, because 21421342973 - 2⁸ = 21421342717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21421342903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710671486 + 10710671487.

It is an arithmetic number, because the mean of its divisors is an integer number (10710671487).

Almost surely, 2^21421342973 is an apocalyptic number.

It is an amenable number.

21421342973 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421342973 is an equidigital number, since it uses as much as digits as its factorization.

21421342973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 38.

The spelling of 21421342973 in words is "twenty-one billion, four hundred twenty-one million, three hundred forty-two thousand, nine hundred seventy-three".