21355101 has 6 divisors (see below), whose sum is σ = 30846270. Its totient is φ = 14236728.

The previous prime is 21355097. The next prime is 21355121. The reversal of 21355101 is 10155312.

It can be written as a sum of positive squares in only one way, i.e., 16818201 + 4536900 = 4101^2 + 2130^2 .

It is not a de Polignac number, because 21355101 - 2² = 21355097 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1186386 + ... + 1186403.

It is an arithmetic number, because the mean of its divisors is an integer number (5141045).

Almost surely, 2^21355101 is an apocalyptic number.

It is an amenable number.

21355101 is a deficient number, since it is larger than the sum of its proper divisors (9491169).

21355101 is a wasteful number, since it uses less digits than its factorization.

21355101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2372795 (or 2372792 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21355101 is about 4621.1579717642. The cubic root of 21355101 is about 277.4388080317.

The spelling of 21355101 in words is "twenty-one million, three hundred fifty-five thousand, one hundred one".