7720638 has 8 divisors (see below), whose sum is σ = 15441288. Its totient is φ = 2573544.

The previous prime is 7720637. The next prime is 7720639. The reversal of 7720638 is 8360277.

It is an interprime number because it is at equal distance from previous prime (7720637) and next prime (7720639).

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

7720638 is an admirable number.

It is a super-2 number, since 2×7720638² = 119216502254088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 7720599 and 7720608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7720633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643381 + ... + 643392.

It is an arithmetic number, because the mean of its divisors is an integer number (1930161).

Almost surely, 2^7720638 is an apocalyptic number.

7720638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

7720638 is a wasteful number, since it uses less digits than its factorization.

7720638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1286778.

The product of its (nonzero) digits is 14112, while the sum is 33.

The square root of 7720638 is about 2778.6036061302. The cubic root of 7720638 is about 197.6443467536.

The spelling of 7720638 in words is "seven million, seven hundred twenty thousand, six hundred thirty-eight".