21018942 has 36 divisors (see below), whose sum is σ = 52978536. Its totient is φ = 6005160.

The previous prime is 21018931. The next prime is 21018947. The reversal of 21018942 is 24981012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018947) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11034 + ... + 12797.

It is an arithmetic number, because the mean of its divisors is an integer number (1471626).

Almost surely, 2^21018942 is an apocalyptic number.

21018942 is an abundant number, since it is smaller than the sum of its proper divisors (31959594).

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

21018942 is a wasteful number, since it uses less digits than its factorization.

21018942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23853 (or 23843 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 21018942 is about 4584.6419707541. The cubic root of 21018942 is about 275.9753443634.

Adding to 21018942 its reverse (24981012), we get a palindrome (45999954).

The spelling of 21018942 in words is "twenty-one million, eighteen thousand, nine hundred forty-two".