421724821787 has 2 divisors, whose sum is σ = 421724821788. Its totient is φ = 421724821786.

The previous prime is 421724821753. The next prime is 421724821829. The reversal of 421724821787 is 787128427124.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421724821787 is a prime.

It is a super-2 number, since 2×421724821787² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (421724821087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210862410893 + 210862410894.

It is an arithmetic number, because the mean of its divisors is an integer number (210862410894).

Almost surely, 2^421724821787 is an apocalyptic number.

421724821787 is a deficient number, since it is larger than the sum of its proper divisors (1).

421724821787 is an equidigital number, since it uses as much as digits as its factorization.

421724821787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2809856, while the sum is 53.

The spelling of 421724821787 in words is "four hundred twenty-one billion, seven hundred twenty-four million, eight hundred twenty-one thousand, seven hundred eighty-seven".