72951021 has 36 divisors (see below), whose sum is σ = 124757724. Its totient is φ = 40803840.

The previous prime is 72951019. The next prime is 72951023. The reversal of 72951021 is 12015927.

It is an interprime number because it is at equal distance from previous prime (72951019) and next prime (72951023).

It can be written as a sum of positive squares in 2 ways, for example, as 27185796 + 45765225 = 5214^2 + 6765^2 .

It is not a de Polignac number, because 72951021 - 2¹ = 72951019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72951023) 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 35 ways as a sum of consecutive naturals, for example, 11581 + ... + 16733.

Almost surely, 2^72951021 is an apocalyptic number.

It is an amenable number.

72951021 is a deficient number, since it is larger than the sum of its proper divisors (51806703).

72951021 is a wasteful number, since it uses less digits than its factorization.

72951021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5194 (or 5180 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 72951021 is about 8541.1369852028. The cubic root of 72951021 is about 417.8404284727.

Adding to 72951021 its reverse (12015927), we get a palindrome (84966948).

The spelling of 72951021 in words is "seventy-two million, nine hundred fifty-one thousand, twenty-one".