20915351 has 4 divisors (see below), whose sum is σ = 21636600. Its totient is φ = 20194104.

The previous prime is 20915341. The next prime is 20915353. The reversal of 20915351 is 15351902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20915351 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20915351.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20915353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 360581 + ... + 360638.

It is an arithmetic number, because the mean of its divisors is an integer number (5409150).

Almost surely, 2^20915351 is an apocalyptic number.

20915351 is a deficient number, since it is larger than the sum of its proper divisors (721249).

20915351 is an equidigital number, since it uses as much as digits as its factorization.

20915351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721248.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 20915351 is about 4573.3304057328. The cubic root of 20915351 is about 275.5212197493.

The spelling of 20915351 in words is "twenty million, nine hundred fifteen thousand, three hundred fifty-one".