1643937121 has 8 divisors (see below), whose sum is σ = 1761776064. Its totient is φ = 1529961840.

The previous prime is 1643937103. The next prime is 1643937131. The reversal of 1643937121 is 1217393461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1643937121 - 2¹³ = 1643928929 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1643937131) 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, 965035 + ... + 966736.

It is an arithmetic number, because the mean of its divisors is an integer number (220222008).

Almost surely, 2^1643937121 is an apocalyptic number.

It is an amenable number.

1643937121 is a deficient number, since it is larger than the sum of its proper divisors (117838943).

1643937121 is a wasteful number, since it uses less digits than its factorization.

1643937121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1931831.

The product of its digits is 27216, while the sum is 37.

The square root of 1643937121 is about 40545.4944599274. The cubic root of 1643937121 is about 1180.2166414931.

The spelling of 1643937121 in words is "one billion, six hundred forty-three million, nine hundred thirty-seven thousand, one hundred twenty-one".