1640534021 has 8 divisors (see below), whose sum is σ = 1875313920. Its totient is φ = 1405858608.

The previous prime is 1640534003. The next prime is 1640534047. The reversal of 1640534021 is 1204350461.

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

It is a de Polignac number, because none of the positive numbers 2^k-1640534021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640531021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11060 + ... + 58338.

It is an arithmetic number, because the mean of its divisors is an integer number (234414240).

Almost surely, 2^1640534021 is an apocalyptic number.

It is an amenable number.

1640534021 is a deficient number, since it is larger than the sum of its proper divisors (234779899).

1640534021 is an equidigital number, since it uses as much as digits as its factorization.

1640534021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52243.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 1640534021 is about 40503.5062803210. The cubic root of 1640534021 is about 1179.4016934784.

Adding to 1640534021 its reverse (1204350461), we get a palindrome (2844884482).

The spelling of 1640534021 in words is "one billion, six hundred forty million, five hundred thirty-four thousand, twenty-one".