400721771 has 2 divisors, whose sum is σ = 400721772. Its totient is φ = 400721770.

The previous prime is 400721767. The next prime is 400721777. The reversal of 400721771 is 177127004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400721771 - 2² = 400721767 is a prime.

It is a Sophie Germain prime.

It is equal to p_21372707 and since 400721771 and 21372707 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (400721777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200360885 + 200360886.

It is an arithmetic number, because the mean of its divisors is an integer number (200360886).

Almost surely, 2^400721771 is an apocalyptic number.

400721771 is a deficient number, since it is larger than the sum of its proper divisors (1).

400721771 is an equidigital number, since it uses as much as digits as its factorization.

400721771 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2744, while the sum is 29.

The square root of 400721771 is about 20018.0361424391. The cubic root of 400721771 is about 737.2492046213.

Adding to 400721771 its reverse (177127004), we get a palindrome (577848775).

The spelling of 400721771 in words is "four hundred million, seven hundred twenty-one thousand, seven hundred seventy-one".