20506977 has 6 divisors (see below), whose sum is σ = 29621202. Its totient is φ = 13671312.

The previous prime is 20506963. The next prime is 20506979. The reversal of 20506977 is 77960502.

It can be written as a sum of positive squares in only one way, i.e., 20466576 + 40401 = 4524^2 + 201^2 .

It is not a de Polignac number, because 20506977 - 2²⁰ = 19458401 is a prime.

It is a super-2 number, since 2×20506977² = 841072211357058, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20506979) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1139268 + ... + 1139285.

It is an arithmetic number, because the mean of its divisors is an integer number (4936867).

Almost surely, 2^20506977 is an apocalyptic number.

It is an amenable number.

20506977 is a deficient number, since it is larger than the sum of its proper divisors (9114225).

20506977 is a wasteful number, since it uses less digits than its factorization.

20506977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2278559 (or 2278556 counting only the distinct ones).

The product of its (nonzero) digits is 26460, while the sum is 36.

The square root of 20506977 is about 4528.4629842806. The cubic root of 20506977 is about 273.7162290235.

The spelling of 20506977 in words is "twenty million, five hundred six thousand, nine hundred seventy-seven".