7721420 has 36 divisors (see below), whose sum is σ = 18864720. Its totient is φ = 2647008.

The previous prime is 7721401. The next prime is 7721423. The reversal of 7721420 is 241277.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7721423) 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 11 ways as a sum of consecutive naturals, for example, 2960 + ... + 4919.

It is an arithmetic number, because the mean of its divisors is an integer number (524020).

Almost surely, 2^7721420 is an apocalyptic number.

7721420 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

7721420 is an abundant number, since it is smaller than the sum of its proper divisors (11143300).

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

7721420 is a wasteful number, since it uses less digits than its factorization.

7721420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7902 (or 7893 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 7721420 is about 2778.7443207319. The cubic root of 7721420 is about 197.6510194604.

Adding to 7721420 its reverse (241277), we get a palindrome (7962697).

The spelling of 7721420 in words is "seven million, seven hundred twenty-one thousand, four hundred twenty".