21146531 has 8 divisors (see below), whose sum is σ = 24223584. Its totient is φ = 18083520.

The previous prime is 21146519. The next prime is 21146533. The reversal of 21146531 is 13564112.

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

It is a de Polignac number, because none of the positive numbers 2^k-21146531 is a prime.

It is a super-2 number, since 2×21146531² = 894351546667922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21146497 and 21146506.

It is not an unprimeable number, because it can be changed into a prime (21146533) 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, 50 + ... + 6503.

It is an arithmetic number, because the mean of its divisors is an integer number (3027948).

Almost surely, 2^21146531 is an apocalyptic number.

21146531 is a deficient number, since it is larger than the sum of its proper divisors (3077053).

21146531 is an equidigital number, since it uses as much as digits as its factorization.

21146531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7021.

The product of its digits is 720, while the sum is 23.

The square root of 21146531 is about 4598.5357452128. The cubic root of 21146531 is about 276.5326259942.

The spelling of 21146531 in words is "twenty-one million, one hundred forty-six thousand, five hundred thirty-one".