21757007 has 2 divisors, whose sum is σ = 21757008. Its totient is φ = 21757006.

The previous prime is 21756997. The next prime is 21757013. The reversal of 21757007 is 70075712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21757007 - 2¹⁴ = 21740623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21757037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10878503 + 10878504.

It is an arithmetic number, because the mean of its divisors is an integer number (10878504).

Almost surely, 2^21757007 is an apocalyptic number.

21757007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21757007 is an equidigital number, since it uses as much as digits as its factorization.

21757007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3430, while the sum is 29.

The square root of 21757007 is about 4664.4406953031. The cubic root of 21757007 is about 279.1684812040.

The spelling of 21757007 in words is "twenty-one million, seven hundred fifty-seven thousand, seven".