21770997 has 4 divisors (see below), whose sum is σ = 29028000. Its totient is φ = 14513996.

The previous prime is 21770993. The next prime is 21771019. The reversal of 21770997 is 79907712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21770997 - 2² = 21770993 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21770993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3628497 + ... + 3628502.

It is an arithmetic number, because the mean of its divisors is an integer number (7257000).

Almost surely, 2^21770997 is an apocalyptic number.

It is an amenable number.

21770997 is a deficient number, since it is larger than the sum of its proper divisors (7257003).

21770997 is an equidigital number, since it uses as much as digits as its factorization.

21770997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7257002.

The product of its (nonzero) digits is 55566, while the sum is 42.

The square root of 21770997 is about 4665.9400982010. The cubic root of 21770997 is about 279.2283045404.

The spelling of 21770997 in words is "twenty-one million, seven hundred seventy thousand, nine hundred ninety-seven".