1640155885 has 8 divisors (see below), whose sum is σ = 1970258040. Its totient is φ = 1310744064.

The previous prime is 1640155873. The next prime is 1640155889. The reversal of 1640155885 is 5885510461.

It can be written as a sum of positive squares in 4 ways, for example, as 1687401 + 1638468484 = 1299^2 + 40478^2 .

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 1640155885 - 2¹⁹ = 1639631597 is a prime.

It is a super-3 number, since 3×1640155885³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640155889) 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, 167340 + ... + 176869.

It is an arithmetic number, because the mean of its divisors is an integer number (246282255).

Almost surely, 2^1640155885 is an apocalyptic number.

It is an amenable number.

1640155885 is a deficient number, since it is larger than the sum of its proper divisors (330102155).

1640155885 is an equidigital number, since it uses as much as digits as its factorization.

1640155885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345167.

The product of its (nonzero) digits is 192000, while the sum is 43.

The square root of 1640155885 is about 40498.8380697521. The cubic root of 1640155885 is about 1179.3110708513.

The spelling of 1640155885 in words is "one billion, six hundred forty million, one hundred fifty-five thousand, eight hundred eighty-five".