21742385 has 16 divisors (see below), whose sum is σ = 30326400. Its totient is φ = 14654976.

The previous prime is 21742381. The next prime is 21742411. The reversal of 21742385 is 58324712.

It is not a de Polignac number, because 21742385 - 2² = 21742381 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21742381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3200 + ... + 7329.

It is an arithmetic number, because the mean of its divisors is an integer number (1895400).

Almost surely, 2^21742385 is an apocalyptic number.

It is an amenable number.

21742385 is a deficient number, since it is larger than the sum of its proper divisors (8584015).

21742385 is a wasteful number, since it uses less digits than its factorization.

21742385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10600.

The product of its digits is 13440, while the sum is 32.

The square root of 21742385 is about 4662.8730413770. The cubic root of 21742385 is about 279.1059279260.

The spelling of 21742385 in words is "twenty-one million, seven hundred forty-two thousand, three hundred eighty-five".