999973421 has 2 divisors, whose sum is σ = 999973422. Its totient is φ = 999973420.

The previous prime is 999973409. The next prime is 999973423. The reversal of 999973421 is 124379999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 986650921 + 13322500 = 31411^2 + 3650^2 .

It is an emirp because it is prime and its reverse (124379999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999973421 - 2⁶ = 999973357 is a prime.

Together with 999973423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999973423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499986710 + 499986711.

It is an arithmetic number, because the mean of its divisors is an integer number (499986711).

Almost surely, 2^999973421 is an apocalyptic number.

It is an amenable number.

999973421 is a deficient number, since it is larger than the sum of its proper divisors (1).

999973421 is an equidigital number, since it uses as much as digits as its factorization.

999973421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1102248, while the sum is 53.

The square root of 999973421 is about 31622.3563480016. The cubic root of 999973421 is about 999.9911402548.

The spelling of 999973421 in words is "nine hundred ninety-nine million, nine hundred seventy-three thousand, four hundred twenty-one".