21428435 has 24 divisors (see below), whose sum is σ = 30164400. Its totient is φ = 14570304.

The previous prime is 21428431. The next prime is 21428453. The reversal of 21428435 is 53482412.

It is a happy number.

It is not a de Polignac number, because 21428435 - 2² = 21428431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21428398 and 21428407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428431) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36212 + ... + 36798.

It is an arithmetic number, because the mean of its divisors is an integer number (1256850).

Almost surely, 2^21428435 is an apocalyptic number.

21428435 is a deficient number, since it is larger than the sum of its proper divisors (8735965).

21428435 is a wasteful number, since it uses less digits than its factorization.

21428435 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755 (or 748 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 21428435 is about 4629.0857628694. The cubic root of 21428435 is about 277.7560226814.

The spelling of 21428435 in words is "twenty-one million, four hundred twenty-eight thousand, four hundred thirty-five".