7121540 has 12 divisors (see below), whose sum is σ = 14955276. Its totient is φ = 2848608.

The previous prime is 7121539. The next prime is 7121573. The reversal of 7121540 is 451217.

It can be written as a sum of positive squares in 2 ways, for example, as 3556996 + 3564544 = 1886^2 + 1888^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 356077 = 7121540 / (7 + 1 + 2 + 1 + 5 + 4 + 0).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178019 + ... + 178058.

It is an arithmetic number, because the mean of its divisors is an integer number (1246273).

Almost surely, 2^7121540 is an apocalyptic number.

It is an amenable number.

7121540 is an abundant number, since it is smaller than the sum of its proper divisors (7833736).

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

7121540 is a wasteful number, since it uses less digits than its factorization.

7121540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356086 (or 356084 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 7121540 is about 2668.6213669234. The cubic root of 7121540 is about 192.3939034178.

Adding to 7121540 its reverse (451217), we get a palindrome (7572757).

The spelling of 7121540 in words is "seven million, one hundred twenty-one thousand, five hundred forty".