400672021 has 2 divisors, whose sum is σ = 400672022. Its totient is φ = 400672020.

The previous prime is 400671991. The next prime is 400672043. The reversal of 400672021 is 120276004.

It is an a-pointer prime, because the next prime (400672043) can be obtained adding 400672021 to its sum of digits (22).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 341843121 + 58828900 = 18489^2 + 7670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400672021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 400671983 and 400672001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400672061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200336010 + 200336011.

It is an arithmetic number, because the mean of its divisors is an integer number (200336011).

Almost surely, 2^400672021 is an apocalyptic number.

It is an amenable number.

400672021 is a deficient number, since it is larger than the sum of its proper divisors (1).

400672021 is an equidigital number, since it uses as much as digits as its factorization.

400672021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 400672021 is about 20016.7934744804. The cubic root of 400672021 is about 737.2186932886.

The spelling of 400672021 in words is "four hundred million, six hundred seventy-two thousand, twenty-one".