21054031 has 4 divisors (see below), whose sum is σ = 21146200. Its totient is φ = 20961864.

The previous prime is 21054017. The next prime is 21054037. The reversal of 21054031 is 13045012.

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

It is a cyclic number.

It is not a de Polignac number, because 21054031 - 2¹⁵ = 21021263 is a prime.

It is a super-2 number, since 2×21054031² = 886544442697922, 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 = 21053996 and 21054014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054037) 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, 45741 + ... + 46198.

It is an arithmetic number, because the mean of its divisors is an integer number (5286550).

Almost surely, 2^21054031 is an apocalyptic number.

21054031 is a deficient number, since it is larger than the sum of its proper divisors (92169).

21054031 is an equidigital number, since it uses as much as digits as its factorization.

21054031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92168.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21054031 is about 4588.4671732508. The cubic root of 21054031 is about 276.1288299701.

Adding to 21054031 its reverse (13045012), we get a palindrome (34099043).

The spelling of 21054031 in words is "twenty-one million, fifty-four thousand, thirty-one".