1999400521 has 4 divisors (see below), whose sum is σ = 2063897344. Its totient is φ = 1934903700.

The previous prime is 1999400519. The next prime is 1999400531. The reversal of 1999400521 is 1250049991.

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 1999400521 - 2¹ = 1999400519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999400531) 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 in 3 ways as a sum of consecutive naturals, for example, 32248365 + ... + 32248426.

It is an arithmetic number, because the mean of its divisors is an integer number (515974336).

Almost surely, 2^1999400521 is an apocalyptic number.

It is an amenable number.

1999400521 is a deficient number, since it is larger than the sum of its proper divisors (64496823).

1999400521 is an equidigital number, since it uses as much as digits as its factorization.

1999400521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64496822.

The product of its (nonzero) digits is 29160, while the sum is 40.

The square root of 1999400521 is about 44714.6566687032. The cubic root of 1999400521 is about 1259.7951546136.

The spelling of 1999400521 in words is "one billion, nine hundred ninety-nine million, four hundred thousand, five hundred twenty-one".