7806640 has 20 divisors (see below), whose sum is σ = 18150624. Its totient is φ = 3122624.

The previous prime is 7806619. The next prime is 7806641. The reversal of 7806640 is 466087.

It is a tau number, because it is divible by the number of its divisors (20).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (7806641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48712 + ... + 48871.

Almost surely, 2^7806640 is an apocalyptic number.

It is an amenable number.

7806640 is an abundant number, since it is smaller than the sum of its proper divisors (10343984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

7806640 is a wasteful number, since it uses less digits than its factorization.

7806640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97596 (or 97590 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 7806640 is about 2794.0365065618. The cubic root of 7806640 is about 198.3755075124.

It can be divided in two parts, 7 and 806640, that multiplied together give a triangular number (5646480 = T₃₃₆₀).

The spelling of 7806640 in words is "seven million, eight hundred six thousand, six hundred forty".