20921151 has 8 divisors (see below), whose sum is σ = 28856880. Its totient is φ = 13466432.

The previous prime is 20921119. The next prime is 20921161. The reversal of 20921151 is 15112902.

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 20921151 - 2⁵ = 20921119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20921161) 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, 120150 + ... + 120323.

It is an arithmetic number, because the mean of its divisors is an integer number (3607110).

Almost surely, 2^20921151 is an apocalyptic number.

20921151 is a deficient number, since it is larger than the sum of its proper divisors (7935729).

20921151 is a wasteful number, since it uses less digits than its factorization.

20921151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240505.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 20921151 is about 4573.9644729709. The cubic root of 20921151 is about 275.5466855006.

The spelling of 20921151 in words is "twenty million, nine hundred twenty-one thousand, one hundred fifty-one".