421165411721 has 2 divisors, whose sum is σ = 421165411722. Its totient is φ = 421165411720.

The previous prime is 421165411687. The next prime is 421165411753. The reversal of 421165411721 is 127114561124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 263051023225 + 158114388496 = 512885^2 + 397636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421165411721 is a prime.

It is not a weakly prime, because it can be changed into another prime (421165411921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210582705860 + 210582705861.

It is an arithmetic number, because the mean of its divisors is an integer number (210582705861).

Almost surely, 2^421165411721 is an apocalyptic number.

It is an amenable number.

421165411721 is a deficient number, since it is larger than the sum of its proper divisors (1).

421165411721 is an equidigital number, since it uses as much as digits as its factorization.

421165411721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

Adding to 421165411721 its reverse (127114561124), we get a palindrome (548279972845).

The spelling of 421165411721 in words is "four hundred twenty-one billion, one hundred sixty-five million, four hundred eleven thousand, seven hundred twenty-one".