1643630477 has 4 divisors (see below), whose sum is σ = 1700307420. Its totient is φ = 1586953536.

The previous prime is 1643630441. The next prime is 1643630489. The reversal of 1643630477 is 7740363461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7740363461 = 8803 ⋅879287.

It can be written as a sum of positive squares in 2 ways, for example, as 1088274121 + 555356356 = 32989^2 + 23566^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643630477 - 2⁶ = 1643630413 is a prime.

It is a super-2 number, since 2×1643630477² = 5403042289846495058, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643630497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28338428 + ... + 28338485.

It is an arithmetic number, because the mean of its divisors is an integer number (425076855).

Almost surely, 2^1643630477 is an apocalyptic number.

It is an amenable number.

1643630477 is a deficient number, since it is larger than the sum of its proper divisors (56676943).

1643630477 is an equidigital number, since it uses as much as digits as its factorization.

1643630477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56676942.

The product of its (nonzero) digits is 254016, while the sum is 41.

The square root of 1643630477 is about 40541.7128029885. The cubic root of 1643630477 is about 1180.1432548955.

The spelling of 1643630477 in words is "one billion, six hundred forty-three million, six hundred thirty thousand, four hundred seventy-seven".