20977739 has 4 divisors (see below), whose sum is σ = 21243360. Its totient is φ = 20712120.

The previous prime is 20977709. The next prime is 20977753. The reversal of 20977739 is 93777902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93777902 = 2 ⋅46888951.

It is a cyclic number.

It is not a de Polignac number, because 20977739 - 2¹² = 20973643 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 20977739.

It is not an unprimeable number, because it can be changed into a prime (20977709) 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, 132692 + ... + 132849.

It is an arithmetic number, because the mean of its divisors is an integer number (5310840).

Almost surely, 2^20977739 is an apocalyptic number.

20977739 is a deficient number, since it is larger than the sum of its proper divisors (265621).

20977739 is an equidigital number, since it uses as much as digits as its factorization.

20977739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265620.

The product of its (nonzero) digits is 166698, while the sum is 44.

The square root of 20977739 is about 4580.1461767066. The cubic root of 20977739 is about 275.7948968043.

The spelling of 20977739 in words is "twenty million, nine hundred seventy-seven thousand, seven hundred thirty-nine".