20699431 has 2 divisors, whose sum is σ = 20699432. Its totient is φ = 20699430.

The previous prime is 20699423. The next prime is 20699473. The reversal of 20699431 is 13499602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20699431 - 2³ = 20699423 is a prime.

It is a super-2 number, since 2×20699431² = 856932887447522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20699401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10349715 + 10349716.

It is an arithmetic number, because the mean of its divisors is an integer number (10349716).

Almost surely, 2^20699431 is an apocalyptic number.

20699431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20699431 is an equidigital number, since it uses as much as digits as its factorization.

20699431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 20699431 is about 4549.6627347530. The cubic root of 20699431 is about 274.5698221969.

It can be divided in two parts, 206994 and 31, that added together give a square (207025 = 455²).

The spelling of 20699431 in words is "twenty million, six hundred ninety-nine thousand, four hundred thirty-one".