451998821 has 2 divisors, whose sum is σ = 451998822. Its totient is φ = 451998820.

The previous prime is 451998803. The next prime is 451998853. The reversal of 451998821 is 128899154.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 277389025 + 174609796 = 16655^2 + 13214^2 .

It is a cyclic number.

It is not a de Polignac number, because 451998821 - 2²⁶ = 384889957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (451998121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 225999410 + 225999411.

It is an arithmetic number, because the mean of its divisors is an integer number (225999411).

Almost surely, 2^451998821 is an apocalyptic number.

It is an amenable number.

451998821 is a deficient number, since it is larger than the sum of its proper divisors (1).

451998821 is an equidigital number, since it uses as much as digits as its factorization.

451998821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 47.

The square root of 451998821 is about 21260.2638977036. The cubic root of 451998821 is about 767.4423606125.

The spelling of 451998821 in words is "four hundred fifty-one million, nine hundred ninety-eight thousand, eight hundred twenty-one".