7640905 has 16 divisors (see below), whose sum is σ = 9774864. Its totient is φ = 5713920.

The previous prime is 7640903. The next prime is 7640909. The reversal of 7640905 is 5090467.

It can be written as a sum of positive squares in 8 ways, for example, as 399424 + 7241481 = 632^2 + 2691^2 .

It is not a de Polignac number, because 7640905 - 2¹ = 7640903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7640903) 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, 20299 + ... + 20671.

It is an arithmetic number, because the mean of its divisors is an integer number (610929).

Almost surely, 2^7640905 is an apocalyptic number.

It is an amenable number.

7640905 is a deficient number, since it is larger than the sum of its proper divisors (2133959).

7640905 is a wasteful number, since it uses less digits than its factorization.

7640905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 7640905 is about 2764.2186961237. The cubic root of 7640905 is about 196.9616165438.

The spelling of 7640905 in words is "seven million, six hundred forty thousand, nine hundred five".