21437442 has 72 divisors (see below), whose sum is σ = 53303796. Its totient is φ = 6188544.

The previous prime is 21437441. The next prime is 21437443. The reversal of 21437442 is 24473412.

21437442 is a `hidden beast` number, since 214 + 3 + 7 + 442 = 666.

It is an interprime number because it is at equal distance from previous prime (21437441) and next prime (21437443).

It can be written as a sum of positive squares in 6 ways, for example, as 7080921 + 14356521 = 2661^2 + 3789^2 .

It is not an unprimeable number, because it can be changed into a prime (21437441) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 67468 + ... + 67784.

Almost surely, 2^21437442 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21437442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26651898).

21437442 is an abundant number, since it is smaller than the sum of its proper divisors (31866354).

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

21437442 is a wasteful number, since it uses less digits than its factorization.

21437442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372 (or 352 counting only the distinct ones).

The product of its digits is 5376, while the sum is 27.

The square root of 21437442 is about 4630.0585309475. The cubic root of 21437442 is about 277.7949335656.

The spelling of 21437442 in words is "twenty-one million, four hundred thirty-seven thousand, four hundred forty-two".