21071157 has 8 divisors (see below), whose sum is σ = 28625184. Its totient is φ = 13782288.

The previous prime is 21071137. The next prime is 21071179. The reversal of 21071157 is 75117012.

It is a happy number.

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

It is not a de Polignac number, because 21071157 - 2⁸ = 21070901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071137) 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, 66103 + ... + 66420.

It is an arithmetic number, because the mean of its divisors is an integer number (3578148).

Almost surely, 2^21071157 is an apocalyptic number.

It is an amenable number.

21071157 is a deficient number, since it is larger than the sum of its proper divisors (7554027).

21071157 is a wasteful number, since it uses less digits than its factorization.

21071157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132579.

The product of its (nonzero) digits is 490, while the sum is 24.

The square root of 21071157 is about 4590.3329944569. The cubic root of 21071157 is about 276.2036802555.

Adding to 21071157 its reverse (75117012), we get a palindrome (96188169).

The spelling of 21071157 in words is "twenty-one million, seventy-one thousand, one hundred fifty-seven".