20408390 has 16 divisors (see below), whose sum is σ = 36786960. Its totient is φ = 8151840.

The previous prime is 20408389. The next prime is 20408393. The reversal of 20408390 is 9380402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20408393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11780 + ... + 13400.

It is an arithmetic number, because the mean of its divisors is an integer number (2299185).

Almost surely, 2^20408390 is an apocalyptic number.

20408390 is a deficient number, since it is larger than the sum of its proper divisors (16378570).

20408390 is a wasteful number, since it uses less digits than its factorization.

20408390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2887.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 20408390 is about 4517.5646093886. The cubic root of 20408390 is about 273.2768952811.

Adding to 20408390 its reverse (9380402), we get a palindrome (29788792).

The spelling of 20408390 in words is "twenty million, four hundred eight thousand, three hundred ninety".