21154101 has 4 divisors (see below), whose sum is σ = 28205472. Its totient is φ = 14102732.

The previous prime is 21154097. The next prime is 21154109. The reversal of 21154101 is 10145112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21154101 - 2² = 21154097 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3525681 + ... + 3525686.

It is an arithmetic number, because the mean of its divisors is an integer number (7051368).

Almost surely, 2^21154101 is an apocalyptic number.

It is an amenable number.

21154101 is a deficient number, since it is larger than the sum of its proper divisors (7051371).

21154101 is an equidigital number, since it uses as much as digits as its factorization.

21154101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7051370.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 21154101 is about 4599.3587596533. The cubic root of 21154101 is about 276.5656196207.

Adding to 21154101 its reverse (10145112), we get a palindrome (31299213).

It can be divided in two parts, 2115 and 4101, that added together give a triangular number (6216 = T₁₁₁).

The spelling of 21154101 in words is "twenty-one million, one hundred fifty-four thousand, one hundred one".