21775037 has 2 divisors, whose sum is σ = 21775038. Its totient is φ = 21775036.

The previous prime is 21775031. The next prime is 21775049. The reversal of 21775037 is 73057712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21771556 + 3481 = 4666^2 + 59^2 .

It is a cyclic number.

It is not a de Polignac number, because 21775037 - 2¹⁸ = 21512893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21774994 and 21775012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21775031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887518 + 10887519.

It is an arithmetic number, because the mean of its divisors is an integer number (10887519).

Almost surely, 2^21775037 is an apocalyptic number.

It is an amenable number.

21775037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21775037 is an equidigital number, since it uses as much as digits as its factorization.

21775037 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10290, while the sum is 32.

The square root of 21775037 is about 4666.3730026649. The cubic root of 21775037 is about 279.2455754165.

The spelling of 21775037 in words is "twenty-one million, seven hundred seventy-five thousand, thirty-seven".