21428570 has 8 divisors (see below), whose sum is σ = 38571444. Its totient is φ = 8571424.

The previous prime is 21428549. The next prime is 21428579. The reversal of 21428570 is 7582412.

It can be written as a sum of positive squares in 2 ways, for example, as 18054001 + 3374569 = 4249^2 + 1837^2 .

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

It is a super-2 number, since 2×21428570² = 918367224489800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21428579) 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, 1071419 + ... + 1071438.

Almost surely, 2^21428570 is an apocalyptic number.

21428570 is a deficient number, since it is larger than the sum of its proper divisors (17142874).

21428570 is a wasteful number, since it uses less digits than its factorization.

21428570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2142864.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21428570 is about 4629.1003445594. The cubic root of 21428570 is about 277.7566059715.

The spelling of 21428570 in words is "twenty-one million, four hundred twenty-eight thousand, five hundred seventy".