1640571523 has 4 divisors (see below), whose sum is σ = 1668377880. Its totient is φ = 1612765168.

The previous prime is 1640571521. The next prime is 1640571539. The reversal of 1640571523 is 3251750461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3251750461 = 21433 ⋅151717.

It is a cyclic number.

It is not a de Polignac number, because 1640571523 - 2¹ = 1640571521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640571521) 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, 13903090 + ... + 13903207.

It is an arithmetic number, because the mean of its divisors is an integer number (417094470).

Almost surely, 2^1640571523 is an apocalyptic number.

1640571523 is a deficient number, since it is larger than the sum of its proper divisors (27806357).

1640571523 is an equidigital number, since it uses as much as digits as its factorization.

1640571523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27806356.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 1640571523 is about 40503.9692252500. The cubic root of 1640571523 is about 1179.4106803052.

The spelling of 1640571523 in words is "one billion, six hundred forty million, five hundred seventy-one thousand, five hundred twenty-three".