20977889 has 2 divisors, whose sum is σ = 20977890. Its totient is φ = 20977888.

The previous prime is 20977871. The next prime is 20977951. The reversal of 20977889 is 98877902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14500864 + 6477025 = 3808^2 + 2545^2 .

It is a cyclic number.

It is not a de Polignac number, because 20977889 - 2¹² = 20973793 is a prime.

It is a super-3 number, since 3×20977889³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20977819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10488944 + 10488945.

It is an arithmetic number, because the mean of its divisors is an integer number (10488945).

Almost surely, 2^20977889 is an apocalyptic number.

It is an amenable number.

20977889 is a deficient number, since it is larger than the sum of its proper divisors (1).

20977889 is an equidigital number, since it uses as much as digits as its factorization.

20977889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 508032, while the sum is 50.

The square root of 20977889 is about 4580.1625517005. The cubic root of 20977889 is about 275.7955541540.

The spelling of 20977889 in words is "twenty million, nine hundred seventy-seven thousand, eight hundred eighty-nine".