21455101 has 2 divisors, whose sum is σ = 21455102. Its totient is φ = 21455100.

The previous prime is 21455087. The next prime is 21455107. The reversal of 21455101 is 10155412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21399876 + 55225 = 4626^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 21455101 - 2⁷ = 21454973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21455107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727550 + 10727551.

It is an arithmetic number, because the mean of its divisors is an integer number (10727551).

Almost surely, 2^21455101 is an apocalyptic number.

It is an amenable number.

21455101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21455101 is an equidigital number, since it uses as much as digits as its factorization.

21455101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21455101 is about 4631.9651337202. The cubic root of 21455101 is about 277.8711900886.

The spelling of 21455101 in words is "twenty-one million, four hundred fifty-five thousand, one hundred one".