20905455 has 8 divisors (see below), whose sum is σ = 33448752. Its totient is φ = 11149568.

The previous prime is 20905429. The next prime is 20905499. The reversal of 20905455 is 55450902.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20905455 - 2¹⁰ = 20904431 is a prime.

It is a super-3 number, since 3×20905455³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 696834 + ... + 696863.

It is an arithmetic number, because the mean of its divisors is an integer number (4181094).

Almost surely, 2^20905455 is an apocalyptic number.

20905455 is a deficient number, since it is larger than the sum of its proper divisors (12543297).

20905455 is a wasteful number, since it uses less digits than its factorization.

20905455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1393705.

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 20905455 is about 4572.2483528347. The cubic root of 20905455 is about 275.4777590376.

The spelling of 20905455 in words is "twenty million, nine hundred five thousand, four hundred fifty-five".