21953803 has 2 divisors, whose sum is σ = 21953804. Its totient is φ = 21953802.

The previous prime is 21953791. The next prime is 21953821. The reversal of 21953803 is 30835912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21953803 is a prime.

It is not a weakly prime, because it can be changed into another prime (21953843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10976901 + 10976902.

It is an arithmetic number, because the mean of its divisors is an integer number (10976902).

Almost surely, 2^21953803 is an apocalyptic number.

21953803 is a deficient number, since it is larger than the sum of its proper divisors (1).

21953803 is an equidigital number, since it uses as much as digits as its factorization.

21953803 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21953803 is about 4685.4885551029. The cubic root of 21953803 is about 280.0076656065.

The spelling of 21953803 in words is "twenty-one million, nine hundred fifty-three thousand, eight hundred three".