21438770 has 8 divisors (see below), whose sum is σ = 38589804. Its totient is φ = 8575504.

The previous prime is 21438757. The next prime is 21438779. The reversal of 21438770 is 7783412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20313049 + 1125721 = 4507^2 + 1061^2 .

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

It is a super-2 number, since 2×21438770² = 919241718225800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21438779) 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, 1071929 + ... + 1071948.

Almost surely, 2^21438770 is an apocalyptic number.

21438770 is a deficient number, since it is larger than the sum of its proper divisors (17151034).

21438770 is a wasteful number, since it uses less digits than its factorization.

21438770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2143884.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 21438770 is about 4630.2019394407. The cubic root of 21438770 is about 277.8006696986.

The spelling of 21438770 in words is "twenty-one million, four hundred thirty-eight thousand, seven hundred seventy".