72405431 has 16 divisors (see below), whose sum is σ = 90642240. Its totient is φ = 56394240.

The previous prime is 72405419. The next prime is 72405439. The reversal of 72405431 is 13450427.

72405431 = T₄₅₀ + T₄₅₁ + ... + T₈₀₆.

It is not a de Polignac number, because 72405431 - 2¹⁰ = 72404407 is a prime.

It is a super-4 number, since 4×72405431⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

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 72405431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72405439) 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 15 ways as a sum of consecutive naturals, for example, 7040 + ... + 13941.

It is an arithmetic number, because the mean of its divisors is an integer number (5665140).

Almost surely, 2^72405431 is an apocalyptic number.

72405431 is a deficient number, since it is larger than the sum of its proper divisors (18236809).

72405431 is a wasteful number, since it uses less digits than its factorization.

72405431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21034.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 72405431 is about 8509.1380879617. The cubic root of 72405431 is about 416.7961650460.

Adding to 72405431 its reverse (13450427), we get a palindrome (85855858).

The spelling of 72405431 in words is "seventy-two million, four hundred five thousand, four hundred thirty-one".