7661640 has 96 divisors (see below), whose sum is σ = 26758080. Its totient is φ = 1749888.

The previous prime is 7661639. The next prime is 7661663. The reversal of 7661640 is 461667.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 7661598 and 7661607.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5229 + ... + 6531.

It is an arithmetic number, because the mean of its divisors is an integer number (278730).

Almost surely, 2^7661640 is an apocalyptic number.

7661640 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7661640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13379040).

7661640 is an abundant number, since it is smaller than the sum of its proper divisors (19096440).

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

7661640 is a wasteful number, since it uses less digits than its factorization.

7661640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1331 (or 1320 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 7661640 is about 2767.9667628062. The cubic root of 7661640 is about 197.1396194745.

It can be divided in two parts, 76 and 61640, that added together give a palindrome (61716).

The spelling of 7661640 in words is "seven million, six hundred sixty-one thousand, six hundred forty".