1640698797 has 4 divisors (see below), whose sum is σ = 2187598400. Its totient is φ = 1093799196.

The previous prime is 1640698789. The next prime is 1640698799. The reversal of 1640698797 is 7978960461.

1640698797 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1640698797 - 2³ = 1640698789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640698799) 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, 273449797 + ... + 273449802.

It is an arithmetic number, because the mean of its divisors is an integer number (546899600).

Almost surely, 2^1640698797 is an apocalyptic number.

It is an amenable number.

1640698797 is a deficient number, since it is larger than the sum of its proper divisors (546899603).

1640698797 is an equidigital number, since it uses as much as digits as its factorization.

1640698797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546899602.

The product of its (nonzero) digits is 4572288, while the sum is 57.

The square root of 1640698797 is about 40505.5403247506. The cubic root of 1640698797 is about 1179.4411787080.

The spelling of 1640698797 in words is "one billion, six hundred forty million, six hundred ninety-eight thousand, seven hundred ninety-seven".