1640541661 has 8 divisors (see below), whose sum is σ = 1796009184. Its totient is φ = 1486128720.

The previous prime is 1640541659. The next prime is 1640541671. The reversal of 1640541661 is 1661450461.

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 1640541661 - 2¹ = 1640541659 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 (1640541671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260386 + ... + 266611.

It is an arithmetic number, because the mean of its divisors is an integer number (224501148).

Almost surely, 2^1640541661 is an apocalyptic number.

1640541661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1640541661 is a deficient number, since it is larger than the sum of its proper divisors (155467523).

1640541661 is a wasteful number, since it uses less digits than its factorization.

1640541661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 527291.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 1640541661 is about 40503.6005930337. The cubic root of 1640541661 is about 1179.4035243080.

The spelling of 1640541661 in words is "one billion, six hundred forty million, five hundred forty-one thousand, six hundred sixty-one".