21156349 has 8 divisors (see below), whose sum is σ = 21533112. Its totient is φ = 20782080.

The previous prime is 21156323. The next prime is 21156371. The reversal of 21156349 is 94365112.

It can be written as a sum of positive squares in 4 ways, for example, as 1416100 + 19740249 = 1190^2 + 4443^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21156349 - 2¹³ = 21148157 is a prime.

It is a super-2 number, since 2×21156349² = 895182206019602, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21156349.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21156049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25359 + ... + 26179.

It is an arithmetic number, because the mean of its divisors is an integer number (2691639).

Almost surely, 2^21156349 is an apocalyptic number.

It is an amenable number.

21156349 is a deficient number, since it is larger than the sum of its proper divisors (376763).

21156349 is an equidigital number, since it uses as much as digits as its factorization.

21156349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247.

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

The square root of 21156349 is about 4599.6031350542. The cubic root of 21156349 is about 276.5754159480.

It can be divided in two parts, 2115 and 6349, that added together give a square (8464 = 92²).

The spelling of 21156349 in words is "twenty-one million, one hundred fifty-six thousand, three hundred forty-nine".