20977551 has 24 divisors (see below), whose sum is σ = 34754720. Its totient is φ = 11943936.

The previous prime is 20977543. The next prime is 20977571. The reversal of 20977551 is 15577902.

It is not a de Polignac number, because 20977551 - 2³ = 20977543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20977531) 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 23 ways as a sum of consecutive naturals, for example, 26895 + ... + 27663.

Almost surely, 2^20977551 is an apocalyptic number.

20977551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20977551 is a deficient number, since it is larger than the sum of its proper divisors (13777169).

20977551 is a wasteful number, since it uses less digits than its factorization.

20977551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1215 (or 1212 counting only the distinct ones).

The product of its (nonzero) digits is 22050, while the sum is 36.

The square root of 20977551 is about 4580.1256532982. The cubic root of 20977551 is about 275.7940729215.

It can be divided in two parts, 20977 and 551, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20977551 in words is "twenty million, nine hundred seventy-seven thousand, five hundred fifty-one".