1640969609 has 16 divisors (see below), whose sum is σ = 1720486656. Its totient is φ = 1563484800.

The previous prime is 1640969597. The next prime is 1640969621. The reversal of 1640969609 is 9069690461.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1640969597) and next prime (1640969621).

It is a cyclic number.

It is not a de Polignac number, because 1640969609 - 2²⁸ = 1372534153 is a prime.

It is a super-2 number, since 2×1640969609² = 5385562515323225762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640969639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1689494 + ... + 1690464.

It is an arithmetic number, because the mean of its divisors is an integer number (107530416).

Almost surely, 2^1640969609 is an apocalyptic number.

It is an amenable number.

1640969609 is a deficient number, since it is larger than the sum of its proper divisors (79517047).

1640969609 is an equidigital number, since it uses as much as digits as its factorization.

1640969609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936.

The product of its (nonzero) digits is 629856, while the sum is 50.

The square root of 1640969609 is about 40508.8830875402. The cubic root of 1640969609 is about 1179.5060675738.

The spelling of 1640969609 in words is "one billion, six hundred forty million, nine hundred sixty-nine thousand, six hundred nine".