20406351 has 16 divisors (see below), whose sum is σ = 31937024. Its totient is φ = 11345184.

The previous prime is 20406349. The next prime is 20406367. The reversal of 20406351 is 15360402.

It is a happy number.

It is not a de Polignac number, because 20406351 - 2¹ = 20406349 is a prime.

It is a super-2 number, since 2×20406351² = 832838322270402, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20406311) 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, 12355 + ... + 13908.

It is an arithmetic number, because the mean of its divisors is an integer number (1996064).

Almost surely, 2^20406351 is an apocalyptic number.

20406351 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20406351 is a deficient number, since it is larger than the sum of its proper divisors (11530673).

20406351 is a wasteful number, since it uses less digits than its factorization.

20406351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26310.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 20406351 is about 4517.3389290599. The cubic root of 20406351 is about 273.2677939565.

Adding to 20406351 its reverse (15360402), we get a palindrome (35766753).

The spelling of 20406351 in words is "twenty million, four hundred six thousand, three hundred fifty-one".