7221620 has 36 divisors (see below), whose sum is σ = 17643780. Its totient is φ = 2475648.

The previous prime is 7221619. The next prime is 7221629. The reversal of 7221620 is 261227.

It can be written as a sum of positive squares in 2 ways, for example, as 4892944 + 2328676 = 2212^2 + 1526^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 7221592 and 7221601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7221629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2705 + ... + 4664.

It is an arithmetic number, because the mean of its divisors is an integer number (490105).

Almost surely, 2^7221620 is an apocalyptic number.

7221620 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

7221620 is an abundant number, since it is smaller than the sum of its proper divisors (10422160).

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

7221620 is a wasteful number, since it uses less digits than its factorization.

7221620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7392 (or 7383 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 7221620 is about 2687.3072023868. The cubic root of 7221620 is about 193.2909604588.

Adding to 7221620 its reverse (261227), we get a palindrome (7482847).

The spelling of 7221620 in words is "seven million, two hundred twenty-one thousand, six hundred twenty".