400021821949 has 2 divisors, whose sum is σ = 400021821950. Its totient is φ = 400021821948.

The previous prime is 400021821943. The next prime is 400021822003. The reversal of 400021821949 is 949128120004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 323158140900 + 76863681049 = 568470^2 + 277243^2 .

It is a cyclic number.

It is not a de Polignac number, because 400021821949 - 2⁷ = 400021821821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400021821943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200010910974 + 200010910975.

It is an arithmetic number, because the mean of its divisors is an integer number (200010910975).

Almost surely, 2^400021821949 is an apocalyptic number.

It is an amenable number.

400021821949 is a deficient number, since it is larger than the sum of its proper divisors (1).

400021821949 is an equidigital number, since it uses as much as digits as its factorization.

400021821949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 40.

The spelling of 400021821949 in words is "four hundred billion, twenty-one million, eight hundred twenty-one thousand, nine hundred forty-nine".