1640464451 has 4 divisors (see below), whose sum is σ = 1644748032. Its totient is φ = 1636180872.

The previous prime is 1640464447. The next prime is 1640464459. The reversal of 1640464451 is 1544640461.

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

It is a cyclic number.

It is not a de Polignac number, because 1640464451 - 2² = 1640464447 is a prime.

It is a super-2 number, since 2×1640464451² = 5382247229989462802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640464459) 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, 2141216 + ... + 2141981.

It is an arithmetic number, because the mean of its divisors is an integer number (411187008).

Almost surely, 2^1640464451 is an apocalyptic number.

1640464451 is a deficient number, since it is larger than the sum of its proper divisors (4283581).

1640464451 is an equidigital number, since it uses as much as digits as its factorization.

1640464451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4283580.

The product of its (nonzero) digits is 46080, while the sum is 35.

The square root of 1640464451 is about 40502.6474566787. The cubic root of 1640464451 is about 1179.3850216438.

The spelling of 1640464451 in words is "one billion, six hundred forty million, four hundred sixty-four thousand, four hundred fifty-one".