72345021 has 24 divisors (see below), whose sum is σ = 112542624. Its totient is φ = 41217120.

The previous prime is 72345019. The next prime is 72345023. The reversal of 72345021 is 12054327.

It is an interprime number because it is at equal distance from previous prime (72345019) and next prime (72345023).

It is not a de Polignac number, because 72345021 - 2¹ = 72345019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 72344982 and 72345000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72345023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76411 + ... + 77351.

It is an arithmetic number, because the mean of its divisors is an integer number (4689276).

Almost surely, 2^72345021 is an apocalyptic number.

It is an amenable number.

72345021 is a deficient number, since it is larger than the sum of its proper divisors (40197603).

72345021 is a wasteful number, since it uses less digits than its factorization.

72345021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1481 (or 1474 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 72345021 is about 8505.5876340204. The cubic root of 72345021 is about 416.6802176571.

Adding to 72345021 its reverse (12054327), we get a palindrome (84399348).

The spelling of 72345021 in words is "seventy-two million, three hundred forty-five thousand, twenty-one".