21973031 has 2 divisors, whose sum is σ = 21973032. Its totient is φ = 21973030.

The previous prime is 21973001. The next prime is 21973033. The reversal of 21973031 is 13037912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21973031 - 2⁶ = 21972967 is a prime.

It is a super-2 number, since 2×21973031² = 965628182653922, which contains 22 as substring.

Together with 21973033, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21973033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10986515 + 10986516.

It is an arithmetic number, because the mean of its divisors is an integer number (10986516).

Almost surely, 2^21973031 is an apocalyptic number.

21973031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21973031 is an equidigital number, since it uses as much as digits as its factorization.

21973031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 21973031 is about 4687.5399731629. The cubic root of 21973031 is about 280.0893889769.

The spelling of 21973031 in words is "twenty-one million, nine hundred seventy-three thousand, thirty-one".