7290021 has 4 divisors (see below), whose sum is σ = 9720032. Its totient is φ = 4860012.

The previous prime is 7290001. The next prime is 7290037. The reversal of 7290021 is 1200927.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 7290021 - 2¹⁵ = 7257253 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 7290021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7290001) 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, 1215001 + ... + 1215006.

It is an arithmetic number, because the mean of its divisors is an integer number (2430008).

Almost surely, 2^7290021 is an apocalyptic number.

It is an amenable number.

7290021 is a deficient number, since it is larger than the sum of its proper divisors (2430011).

7290021 is a wasteful number, since it uses less digits than its factorization.

7290021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430010.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 7290021 is about 2700.0038888861. The cubic root of 7290021 is about 193.8993082884.

Subtracting from 7290021 its sum of digits (21), we obtain a square (7290000 = 2700²).

Adding to 7290021 its reverse (1200927), we get a palindrome (8490948).

The spelling of 7290021 in words is "seven million, two hundred ninety thousand, twenty-one".