400826021 has 2 divisors, whose sum is σ = 400826022. Its totient is φ = 400826020.

The previous prime is 400825981. The next prime is 400826057. The reversal of 400826021 is 120628004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 353064100 + 47761921 = 18790^2 + 6911^2 .

It is a cyclic number.

It is not a de Polignac number, because 400826021 - 2²² = 396631717 is a prime.

It is a super-2 number, since 2×400826021² = 321322998221384882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400826821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200413010 + 200413011.

It is an arithmetic number, because the mean of its divisors is an integer number (200413011).

Almost surely, 2^400826021 is an apocalyptic number.

It is an amenable number.

400826021 is a deficient number, since it is larger than the sum of its proper divisors (1).

400826021 is an equidigital number, since it uses as much as digits as its factorization.

400826021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 400826021 is about 20020.6398748891. The cubic root of 400826021 is about 737.3131322399.

The spelling of 400826021 in words is "four hundred million, eight hundred twenty-six thousand, twenty-one".