1640634634 has 4 divisors (see below), whose sum is σ = 2460951954. Its totient is φ = 820317316.

The previous prime is 1640634617. The next prime is 1640634637. The reversal of 1640634634 is 4364360461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4364360461 = 127 ⋅34365043.

It can be written as a sum of positive squares in only one way, i.e., 1548186409 + 92448225 = 39347^2 + 9615^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1640634593 and 1640634602.

It is not an unprimeable number, because it can be changed into a prime (1640634637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410158657 + ... + 410158660.

Almost surely, 2^1640634634 is an apocalyptic number.

1640634634 is a deficient number, since it is larger than the sum of its proper divisors (820317320).

1640634634 is an equidigital number, since it uses as much as digits as its factorization.

1640634634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820317319.

The product of its (nonzero) digits is 124416, while the sum is 37.

The square root of 1640634634 is about 40504.7482895524. The cubic root of 1640634634 is about 1179.4258036594.

It can be divided in two parts, 16406 and 34634, that added together give a triangular number (51040 = T₃₁₉).

The spelling of 1640634634 in words is "one billion, six hundred forty million, six hundred thirty-four thousand, six hundred thirty-four".