21400793 has 2 divisors, whose sum is σ = 21400794. Its totient is φ = 21400792.

The previous prime is 21400781. The next prime is 21400801. The reversal of 21400793 is 39700412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19245769 + 2155024 = 4387^2 + 1468^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400793 - 2¹⁶ = 21335257 is a prime.

It is not a weakly prime, because it can be changed into another prime (21400723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700396 + 10700397.

It is an arithmetic number, because the mean of its divisors is an integer number (10700397).

Almost surely, 2^21400793 is an apocalyptic number.

It is an amenable number.

21400793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400793 is an equidigital number, since it uses as much as digits as its factorization.

21400793 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21400793 is about 4626.0991126434. The cubic root of 21400793 is about 277.6365391433.

The spelling of 21400793 in words is "twenty-one million, four hundred thousand, seven hundred ninety-three".