20421151 has 8 divisors (see below), whose sum is σ = 21032240. Its totient is φ = 19813248.

The previous prime is 20421103. The next prime is 20421179. The reversal of 20421151 is 15112402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20421151 - 2⁹ = 20420639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421251) 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, 19735 + ... + 20743.

It is an arithmetic number, because the mean of its divisors is an integer number (2629030).

Almost surely, 2^20421151 is an apocalyptic number.

20421151 is a deficient number, since it is larger than the sum of its proper divisors (611089).

20421151 is a wasteful number, since it uses less digits than its factorization.

20421151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1593.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 20421151 is about 4518.9767647112. The cubic root of 20421151 is about 273.3338417930. Note that the first 3 decimals are identical.

Adding to 20421151 its reverse (15112402), we get a palindrome (35533553).

The spelling of 20421151 in words is "twenty million, four hundred twenty-one thousand, one hundred fifty-one".