1640743557 has 8 divisors (see below), whose sum is σ = 2187878784. Its totient is φ = 1093718688.

The previous prime is 1640743553. The next prime is 1640743589. The reversal of 1640743557 is 7553470461.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1640743557 - 2² = 1640743553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640743553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17748 + ... + 59970.

It is an arithmetic number, because the mean of its divisors is an integer number (273484848).

Almost surely, 2^1640743557 is an apocalyptic number.

It is an amenable number.

1640743557 is a deficient number, since it is larger than the sum of its proper divisors (547135227).

1640743557 is a wasteful number, since it uses less digits than its factorization.

1640743557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55179.

The product of its (nonzero) digits is 352800, while the sum is 42.

The square root of 1640743557 is about 40506.0928379917. The cubic root of 1640743557 is about 1179.4519040784.

The spelling of 1640743557 in words is "one billion, six hundred forty million, seven hundred forty-three thousand, five hundred fifty-seven".