72007021 has 4 divisors (see below), whose sum is σ = 72024192. Its totient is φ = 71989852.

The previous prime is 72007009. The next prime is 72007027. The reversal of 72007021 is 12070027.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12070027 = 193 ⋅62539.

It is a cyclic number.

It is not a de Polignac number, because 72007021 - 2²¹ = 69909869 is a prime.

It is a super-2 number, since 2×72007021² = 10370022146588882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72007021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72007027) 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, 2340 + ... + 12226.

It is an arithmetic number, because the mean of its divisors is an integer number (18006048).

Almost surely, 2^72007021 is an apocalyptic number.

It is an amenable number.

72007021 is a deficient number, since it is larger than the sum of its proper divisors (17171).

72007021 is an equidigital number, since it uses as much as digits as its factorization.

72007021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17170.

The product of its (nonzero) digits is 196, while the sum is 19.

The square root of 72007021 is about 8485.6950805458. The cubic root of 72007021 is about 416.0302866417.

Adding to 72007021 its reverse (12070027), we get a palindrome (84077048).

The spelling of 72007021 in words is "seventy-two million, seven thousand, twenty-one".