21407434 has 8 divisors (see below), whose sum is σ = 33507360. Its totient is φ = 10238316.

The previous prime is 21407387. The next prime is 21407467. The reversal of 21407434 is 43470412.

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

It is a junction number, because it is equal to n+sod(n) for n = 21407399 and 21407408.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 232644 + ... + 232735.

It is an arithmetic number, because the mean of its divisors is an integer number (4188420).

Almost surely, 2^21407434 is an apocalyptic number.

21407434 is a deficient number, since it is larger than the sum of its proper divisors (12099926).

21407434 is a wasteful number, since it uses less digits than its factorization.

21407434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465404.

The product of its (nonzero) digits is 2688, while the sum is 25.

The square root of 21407434 is about 4626.8168323373. The cubic root of 21407434 is about 277.6652544900.

Adding to 21407434 its reverse (43470412), we get a palindrome (64877846).

The spelling of 21407434 in words is "twenty-one million, four hundred seven thousand, four hundred thirty-four".