20977215 has 16 divisors (see below), whose sum is σ = 38358528. Its totient is φ = 9589536.

The previous prime is 20977193. The next prime is 20977217. The reversal of 20977215 is 51277902.

It is not a de Polignac number, because 20977215 - 2¹¹ = 20975167 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20977217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99787 + ... + 99996.

It is an arithmetic number, because the mean of its divisors is an integer number (2397408).

Almost surely, 2^20977215 is an apocalyptic number.

20977215 is a deficient number, since it is larger than the sum of its proper divisors (17381313).

20977215 is a wasteful number, since it uses less digits than its factorization.

20977215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199798.

The product of its (nonzero) digits is 8820, while the sum is 33.

The square root of 20977215 is about 4580.0889729349. The cubic root of 20977215 is about 275.7926004378.

The spelling of 20977215 in words is "twenty million, nine hundred seventy-seven thousand, two hundred fifteen".