21789157 has 8 divisors (see below), whose sum is σ = 23534336. Its totient is φ = 20053872.

The previous prime is 21789151. The next prime is 21789167. The reversal of 21789157 is 75198712.

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 21789157 - 2¹⁹ = 21264869 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 (21789151) 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, 2488 + ... + 7054.

It is an arithmetic number, because the mean of its divisors is an integer number (2941792).

Almost surely, 2^21789157 is an apocalyptic number.

It is an amenable number.

21789157 is a deficient number, since it is larger than the sum of its proper divisors (1745179).

21789157 is a wasteful number, since it uses less digits than its factorization.

21789157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4947.

The product of its digits is 35280, while the sum is 40.

The square root of 21789157 is about 4667.8857098262. The cubic root of 21789157 is about 279.3059212086.

The spelling of 21789157 in words is "twenty-one million, seven hundred eighty-nine thousand, one hundred fifty-seven".