401009621 has 2 divisors, whose sum is σ = 401009622. Its totient is φ = 401009620.

The previous prime is 401009599. The next prime is 401009627. The reversal of 401009621 is 126900104.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 257249521 + 143760100 = 16039^2 + 11990^2 .

It is a cyclic number.

It is not a de Polignac number, because 401009621 - 2²² = 396815317 is a prime.

It is a super-3 number, since 3×401009621³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401009627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200504810 + 200504811.

It is an arithmetic number, because the mean of its divisors is an integer number (200504811).

Almost surely, 2^401009621 is an apocalyptic number.

It is an amenable number.

401009621 is a deficient number, since it is larger than the sum of its proper divisors (1).

401009621 is an equidigital number, since it uses as much as digits as its factorization.

401009621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 401009621 is about 20025.2246179662. The cubic root of 401009621 is about 737.4256914885.

Adding to 401009621 its reverse (126900104), we get a palindrome (527909725).

The spelling of 401009621 in words is "four hundred one million, nine thousand, six hundred twenty-one".