21315029 has 4 divisors (see below), whose sum is σ = 22050060. Its totient is φ = 20580000.

The previous prime is 21315023. The next prime is 21315031. The reversal of 21315029 is 92051312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4092529 + 17222500 = 2023^2 + 4150^2 .

It is a cyclic number.

It is not a de Polignac number, because 21315029 - 2⁴ = 21315013 is a prime.

It is a super-2 number, since 2×21315029² = 908660922541682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21314995 and 21315013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 367472 + ... + 367529.

It is an arithmetic number, because the mean of its divisors is an integer number (5512515).

Almost surely, 2^21315029 is an apocalyptic number.

21315029 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21315029 is a deficient number, since it is larger than the sum of its proper divisors (735031).

21315029 is an equidigital number, since it uses as much as digits as its factorization.

21315029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 735030.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21315029 is about 4616.8202260863. The cubic root of 21315029 is about 277.2651650686.

The spelling of 21315029 in words is "twenty-one million, three hundred fifteen thousand, twenty-nine".