21157750 has 16 divisors (see below), whose sum is σ = 39607776. Its totient is φ = 8463000.

The previous prime is 21157739. The next prime is 21157751. The reversal of 21157750 is 5775112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157751) 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, 42066 + ... + 42565.

It is an arithmetic number, because the mean of its divisors is an integer number (2475486).

Almost surely, 2^21157750 is an apocalyptic number.

21157750 is a deficient number, since it is larger than the sum of its proper divisors (18450026).

21157750 is an equidigital number, since it uses as much as digits as its factorization.

21157750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84648 (or 84638 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 21157750 is about 4599.7554282809. The cubic root of 21157750 is about 276.5815208704.

The spelling of 21157750 in words is "twenty-one million, one hundred fifty-seven thousand, seven hundred fifty".