21751403 has 2 divisors, whose sum is σ = 21751404. Its totient is φ = 21751402.

The previous prime is 21751393. The next prime is 21751423. The reversal of 21751403 is 30415712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21751403 - 2⁶ = 21751339 is a prime.

It is not a weakly prime, because it can be changed into another prime (21751423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10875701 + 10875702.

It is an arithmetic number, because the mean of its divisors is an integer number (10875702).

Almost surely, 2^21751403 is an apocalyptic number.

21751403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21751403 is an equidigital number, since it uses as much as digits as its factorization.

21751403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21751403 is about 4663.8399415074. The cubic root of 21751403 is about 279.1445104666.

The spelling of 21751403 in words is "twenty-one million, seven hundred fifty-one thousand, four hundred three".