1638540757 has 16 divisors (see below), whose sum is σ = 1930001920. Its totient is φ = 1361897712.

The previous prime is 1638540749. The next prime is 1638540763. The reversal of 1638540757 is 7570458361.

It is not a de Polignac number, because 1638540757 - 2³ = 1638540749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638540737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22258 + ... + 61420.

It is an arithmetic number, because the mean of its divisors is an integer number (120625120).

Almost surely, 2^1638540757 is an apocalyptic number.

It is an amenable number.

1638540757 is a deficient number, since it is larger than the sum of its proper divisors (291461163).

1638540757 is a wasteful number, since it uses less digits than its factorization.

1638540757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39352.

The product of its (nonzero) digits is 705600, while the sum is 46.

The square root of 1638540757 is about 40478.8927343622. The cubic root of 1638540757 is about 1178.9238385736.

The spelling of 1638540757 in words is "one billion, six hundred thirty-eight million, five hundred forty thousand, seven hundred fifty-seven".