21520342 has 8 divisors (see below), whose sum is σ = 32310432. Its totient is φ = 10750200.

The previous prime is 21520307. The next prime is 21520361. The reversal of 21520342 is 24302512.

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

It is a congruent number.

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, 1909 + ... + 6832.

It is an arithmetic number, because the mean of its divisors is an integer number (4038804).

Almost surely, 2^21520342 is an apocalyptic number.

21520342 is a deficient number, since it is larger than the sum of its proper divisors (10790090).

21520342 is a wasteful number, since it uses less digits than its factorization.

21520342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9974.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21520342 is about 4639.0022634183. The cubic root of 21520342 is about 278.1525567444.

Adding to 21520342 its reverse (24302512), we get a palindrome (45822854).

The spelling of 21520342 in words is "twenty-one million, five hundred twenty thousand, three hundred forty-two".