7121665 has 8 divisors (see below), whose sum is σ = 8608320. Its totient is φ = 5655792.

The previous prime is 7121629. The next prime is 7121669. The reversal of 7121665 is 5661217.

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

It is a cyclic number.

It is not a de Polignac number, because 7121665 - 2¹⁵ = 7088897 is a prime.

It is a super-2 number, since 2×7121665² = 101436224744450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7121669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4429 + ... + 5818.

It is an arithmetic number, because the mean of its divisors is an integer number (1076040).

Almost surely, 2^7121665 is an apocalyptic number.

It is an amenable number.

7121665 is a deficient number, since it is larger than the sum of its proper divisors (1486655).

7121665 is a wasteful number, since it uses less digits than its factorization.

7121665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10391.

The product of its digits is 2520, while the sum is 28.

The square root of 7121665 is about 2668.6447871532. The cubic root of 7121665 is about 192.3950290684.

It can be divided in two parts, 71 and 21665, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 7121665 in words is "seven million, one hundred twenty-one thousand, six hundred sixty-five".