20402397 has 12 divisors (see below), whose sum is σ = 31203900. Its totient is φ = 12801408.

The previous prime is 20402387. The next prime is 20402407. The reversal of 20402397 is 79320402.

It is an interprime number because it is at equal distance from previous prime (20402387) and next prime (20402407).

It can be written as a sum of positive squares in 2 ways, for example, as 9865881 + 10536516 = 3141^2 + 3246^2 .

It is not a de Polignac number, because 20402397 - 2⁴ = 20402381 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20402397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20402387) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66522 + ... + 66827.

It is an arithmetic number, because the mean of its divisors is an integer number (2600325).

Almost surely, 2^20402397 is an apocalyptic number.

It is an amenable number.

20402397 is a deficient number, since it is larger than the sum of its proper divisors (10801503).

20402397 is a wasteful number, since it uses less digits than its factorization.

20402397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133372 (or 133369 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 20402397 is about 4516.9012608203. The cubic root of 20402397 is about 273.2501430684.

Adding to 20402397 its reverse (79320402), we get a palindrome (99722799).

The spelling of 20402397 in words is "twenty million, four hundred two thousand, three hundred ninety-seven".