400611521 has 4 divisors (see below), whose sum is σ = 409928112. Its totient is φ = 391294932.

The previous prime is 400611499. The next prime is 400611529. The reversal of 400611521 is 125116004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 400611521 - 2¹⁸ = 400349377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 400611493 and 400611502.

It is not an unprimeable number, because it can be changed into a prime (400611529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4658231 + ... + 4658316.

It is an arithmetic number, because the mean of its divisors is an integer number (102482028).

Almost surely, 2^400611521 is an apocalyptic number.

It is an amenable number.

400611521 is a deficient number, since it is larger than the sum of its proper divisors (9316591).

400611521 is an equidigital number, since it uses as much as digits as its factorization.

400611521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9316590.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 400611521 is about 20015.2821863695. The cubic root of 400611521 is about 737.1815856513.

Adding to 400611521 its reverse (125116004), we get a palindrome (525727525).

The spelling of 400611521 in words is "four hundred million, six hundred eleven thousand, five hundred twenty-one".