21142031 has 4 divisors (see below), whose sum is σ = 21824064. Its totient is φ = 20460000.

The previous prime is 21142021. The next prime is 21142061. The reversal of 21142031 is 13024112.

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

It is not a de Polignac number, because 21142031 - 2¹⁰ = 21141007 is a prime.

It is a super-2 number, since 2×21142031² = 893970949609922, 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 = 21141997 and 21142015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142021) 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, 340970 + ... + 341031.

It is an arithmetic number, because the mean of its divisors is an integer number (5456016).

Almost surely, 2^21142031 is an apocalyptic number.

21142031 is a deficient number, since it is larger than the sum of its proper divisors (682033).

21142031 is an equidigital number, since it uses as much as digits as its factorization.

21142031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 682032.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21142031 is about 4598.0464329974. The cubic root of 21142031 is about 276.5130091424.

Adding to 21142031 its reverse (13024112), we get a palindrome (34166143).

The spelling of 21142031 in words is "twenty-one million, one hundred forty-two thousand, thirty-one".