21513270 has 16 divisors (see below), whose sum is σ = 51631920. Its totient is φ = 5736864.

The previous prime is 21513269. The next prime is 21513277. The reversal of 21513270 is 7231512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21513277) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 358525 + ... + 358584.

It is an arithmetic number, because the mean of its divisors is an integer number (3226995).

Almost surely, 2^21513270 is an apocalyptic number.

21513270 is an abundant number, since it is smaller than the sum of its proper divisors (30118650).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21513270 is a wasteful number, since it uses less digits than its factorization.

21513270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717119.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21513270 is about 4638.2399679189. The cubic root of 21513270 is about 278.1220846389.

Adding to 21513270 its reverse (7231512), we get a palindrome (28744782).

The spelling of 21513270 in words is "twenty-one million, five hundred thirteen thousand, two hundred seventy".