21053742 has 8 divisors (see below), whose sum is σ = 42107496. Its totient is φ = 7017912.

The previous prime is 21053741. The next prime is 21053783. The reversal of 21053742 is 24735012.

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

21053742 is an admirable number.

It is a super-3 number, since 3×21053742³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21053741) 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, 1754473 + ... + 1754484.

It is an arithmetic number, because the mean of its divisors is an integer number (5263437).

Almost surely, 2^21053742 is an apocalyptic number.

21053742 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21053742 is a wasteful number, since it uses less digits than its factorization.

21053742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3508962.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21053742 is about 4588.4356811445. The cubic root of 21053742 is about 276.1275665288.

Adding to 21053742 its reverse (24735012), we get a palindrome (45788754).

The spelling of 21053742 in words is "twenty-one million, fifty-three thousand, seven hundred forty-two".