1640400421 has 8 divisors (see below), whose sum is σ = 1831145184. Its totient is φ = 1456591920.

The previous prime is 1640400413. The next prime is 1640400449. The reversal of 1640400421 is 1240040461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1640400421 - 2³ = 1640400413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1640400392 and 1640400401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640400221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1733566 + ... + 1734511.

It is an arithmetic number, because the mean of its divisors is an integer number (228893148).

Almost surely, 2^1640400421 is an apocalyptic number.

1640400421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1640400421 is a deficient number, since it is larger than the sum of its proper divisors (190744763).

1640400421 is a wasteful number, since it uses less digits than its factorization.

1640400421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3468131.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 1640400421 is about 40501.8570068090. The cubic root of 1640400421 is about 1179.3696770045.

Adding to 1640400421 its reverse (1240040461), we get a palindrome (2880440882).

The spelling of 1640400421 in words is "one billion, six hundred forty million, four hundred thousand, four hundred twenty-one".