1643642156 has 24 divisors (see below), whose sum is σ = 3120257280. Its totient is φ = 753063552.

The previous prime is 1643642113. The next prime is 1643642159. The reversal of 1643642156 is 6512463461.

It is not an unprimeable number, because it can be changed into a prime (1643642159) 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, 108236 + ... + 122483.

It is an arithmetic number, because the mean of its divisors is an integer number (130010720).

Almost surely, 2^1643642156 is an apocalyptic number.

It is an amenable number.

1643642156 is a deficient number, since it is larger than the sum of its proper divisors (1476615124).

1643642156 is a wasteful number, since it uses less digits than its factorization.

1643642156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230873 (or 230871 counting only the distinct ones).

The product of its digits is 103680, while the sum is 38.

The square root of 1643642156 is about 40541.8568395677. The cubic root of 1643642156 is about 1180.1460501021.

The spelling of 1643642156 in words is "one billion, six hundred forty-three million, six hundred forty-two thousand, one hundred fifty-six".