20997142 has 16 divisors (see below), whose sum is σ = 33438960. Its totient is φ = 9854208.

The previous prime is 20997139. The next prime is 20997143. The reversal of 20997142 is 24179902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 20997098 and 20997107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18034 + ... + 19162.

It is an arithmetic number, because the mean of its divisors is an integer number (2089935).

Almost surely, 2^20997142 is an apocalyptic number.

20997142 is a deficient number, since it is larger than the sum of its proper divisors (12441818).

20997142 is a wasteful number, since it uses less digits than its factorization.

20997142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1695.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 20997142 is about 4582.2638509802. The cubic root of 20997142 is about 275.8799011889.

The spelling of 20997142 in words is "twenty million, nine hundred ninety-seven thousand, one hundred forty-two".