1640365321 has 4 divisors (see below), whose sum is σ = 1874703232. Its totient is φ = 1406027412.

The previous prime is 1640365277. The next prime is 1640365339. The reversal of 1640365321 is 1235630461.

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 1640365321 - 2¹³ = 1640357129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640365381) 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, 117168945 + ... + 117168958.

It is an arithmetic number, because the mean of its divisors is an integer number (468675808).

Almost surely, 2^1640365321 is an apocalyptic number.

It is an amenable number.

1640365321 is a deficient number, since it is larger than the sum of its proper divisors (234337911).

1640365321 is an equidigital number, since it uses as much as digits as its factorization.

1640365321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234337910.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 1640365321 is about 40501.4236910260. The cubic root of 1640365321 is about 1179.3612652025.

Adding to 1640365321 its reverse (1235630461), we get a palindrome (2875995782).

The spelling of 1640365321 in words is "one billion, six hundred forty million, three hundred sixty-five thousand, three hundred twenty-one".