7972021 has 4 divisors (see below), whose sum is σ = 8107200. Its totient is φ = 7836844.

The previous prime is 7972009. The next prime is 7972033. The reversal of 7972021 is 1202797.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1202797 = 421 ⋅2857.

It is an interprime number because it is at equal distance from previous prime (7972009) and next prime (7972033).

It is a cyclic number.

It is not a de Polignac number, because 7972021 - 2¹⁷ = 7840949 is a prime.

It is a Duffinian number.

7972021 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7972051) 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 3 ways as a sum of consecutive naturals, for example, 67501 + ... + 67618.

It is an arithmetic number, because the mean of its divisors is an integer number (2026800).

Almost surely, 2^7972021 is an apocalyptic number.

It is an amenable number.

7972021 is a deficient number, since it is larger than the sum of its proper divisors (135179).

7972021 is a wasteful number, since it uses less digits than its factorization.

7972021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135178.

The product of its (nonzero) digits is 1764, while the sum is 28.

The square root of 7972021 is about 2823.4767574747. The cubic root of 7972021 is about 199.7665693233.

The spelling of 7972021 in words is "seven million, nine hundred seventy-two thousand, twenty-one".