401561673421 has 2 divisors, whose sum is σ = 401561673422. Its totient is φ = 401561673420.

The previous prime is 401561673349. The next prime is 401561673427. The reversal of 401561673421 is 124376165104.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259066748196 + 142494925225 = 508986^2 + 377485^2 .

It is a cyclic number.

It is not a de Polignac number, because 401561673421 - 2¹⁵ = 401561640653 is a prime.

It is a super-2 number, since 2×401561673421² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401561673427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200780836710 + 200780836711.

It is an arithmetic number, because the mean of its divisors is an integer number (200780836711).

Almost surely, 2^401561673421 is an apocalyptic number.

It is an amenable number.

401561673421 is a deficient number, since it is larger than the sum of its proper divisors (1).

401561673421 is an equidigital number, since it uses as much as digits as its factorization.

401561673421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 401561673421 in words is "four hundred one billion, five hundred sixty-one million, six hundred seventy-three thousand, four hundred twenty-one".