21751842 has 16 divisors (see below), whose sum is σ = 49718592. Its totient is φ = 6214800.

The previous prime is 21751841. The next prime is 21751843. The reversal of 21751842 is 24815712.

It is an interprime number because it is at equal distance from previous prime (21751841) and next prime (21751843).

It is not an unprimeable number, because it can be changed into a prime (21751841) 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 7 ways as a sum of consecutive naturals, for example, 258909 + ... + 258992.

It is an arithmetic number, because the mean of its divisors is an integer number (3107412).

Almost surely, 2^21751842 is an apocalyptic number.

21751842 is an abundant number, since it is smaller than the sum of its proper divisors (27966750).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21751842 is a wasteful number, since it uses less digits than its factorization.

21751842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517913.

The product of its digits is 4480, while the sum is 30.

The square root of 21751842 is about 4663.8870054923. The cubic root of 21751842 is about 279.1463884085.

The spelling of 21751842 in words is "twenty-one million, seven hundred fifty-one thousand, eight hundred forty-two".