9720405 has 20 divisors (see below), whose sum is σ = 17425452. Its totient is φ = 5184000.

The previous prime is 9720383. The next prime is 9720407. The reversal of 9720405 is 5040279.

It can be written as a sum of positive squares in 2 ways, for example, as 3048516 + 6671889 = 1746^2 + 2583^2 .

It is not a de Polignac number, because 9720405 - 2⁸ = 9720149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

9720405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9720407) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11596 + ... + 12405.

Almost surely, 2^9720405 is an apocalyptic number.

It is an amenable number.

9720405 is a deficient number, since it is larger than the sum of its proper divisors (7705047).

9720405 is a wasteful number, since it uses less digits than its factorization.

9720405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24018 (or 24009 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 9720405 is about 3117.7564048527. The cubic root of 9720405 is about 213.4165623060.

It can be divided in two parts, 97 and 20405, that added together give a palindrome (20502).

The spelling of 9720405 in words is "nine million, seven hundred twenty thousand, four hundred five".