21977719 has 8 divisors (see below), whose sum is σ = 24282720. Its totient is φ = 19785216.

The previous prime is 21977713. The next prime is 21977743. The reversal of 21977719 is 91777912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21977719 - 2⁷ = 21977591 is a prime.

It is a super-2 number, since 2×21977719² = 966040264885922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977713) 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, 27714 + ... + 28495.

It is an arithmetic number, because the mean of its divisors is an integer number (3035340).

Almost surely, 2^21977719 is an apocalyptic number.

21977719 is a deficient number, since it is larger than the sum of its proper divisors (2305001).

21977719 is a wasteful number, since it uses less digits than its factorization.

21977719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56249.

The product of its digits is 55566, while the sum is 43.

The square root of 21977719 is about 4688.0399955632. The cubic root of 21977719 is about 280.1093068129.

The spelling of 21977719 in words is "twenty-one million, nine hundred seventy-seven thousand, seven hundred nineteen".