20997436 has 12 divisors (see below), whose sum is σ = 38343312. Its totient is φ = 10042208.

The previous prime is 20997419. The next prime is 20997437. The reversal of 20997436 is 63479902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997437) 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, 114025 + ... + 114208.

It is an arithmetic number, because the mean of its divisors is an integer number (3195276).

Almost surely, 2^20997436 is an apocalyptic number.

It is an amenable number.

20997436 is a deficient number, since it is larger than the sum of its proper divisors (17345876).

20997436 is a wasteful number, since it uses less digits than its factorization.

20997436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228260 (or 228258 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 40.

The square root of 20997436 is about 4582.2959310808. The cubic root of 20997436 is about 275.8811887976.

The spelling of 20997436 in words is "twenty million, nine hundred ninety-seven thousand, four hundred thirty-six".