1640655026 has 4 divisors (see below), whose sum is σ = 2460982542. Its totient is φ = 820327512.

The previous prime is 1640655017. The next prime is 1640655041. The reversal of 1640655026 is 6205560461.

It is a Cunningham number, because it is equal to 40505²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1640655025 + 1 = 40505^2 + 1^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410163755 + ... + 410163758.

Almost surely, 2^1640655026 is an apocalyptic number.

1640655026 is a deficient number, since it is larger than the sum of its proper divisors (820327516).

1640655026 is an equidigital number, since it uses as much as digits as its factorization.

1640655026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820327515.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 1640655026 is about 40505.0000123442. Note that the first 4 decimals coincide. The cubic root of 1640655026 is about 1179.4306901326.

The spelling of 1640655026 in words is "one billion, six hundred forty million, six hundred fifty-five thousand, twenty-six".