21746157 has 4 divisors (see below), whose sum is σ = 28994880. Its totient is φ = 14497436.

The previous prime is 21746149. The next prime is 21746177. The reversal of 21746157 is 75164712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21746157 - 2³ = 21746149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21746117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3624357 + ... + 3624362.

It is an arithmetic number, because the mean of its divisors is an integer number (7248720).

Almost surely, 2^21746157 is an apocalyptic number.

It is an amenable number.

21746157 is a deficient number, since it is larger than the sum of its proper divisors (7248723).

21746157 is an equidigital number, since it uses as much as digits as its factorization.

21746157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7248722.

The product of its digits is 11760, while the sum is 33.

The square root of 21746157 is about 4663.2774954961. The cubic root of 21746157 is about 279.1220673189.

The spelling of 21746157 in words is "twenty-one million, seven hundred forty-six thousand, one hundred fifty-seven".