21378797 has 8 divisors (see below), whose sum is σ = 23399712. Its totient is φ = 19370800.

The previous prime is 21378767. The next prime is 21378817. The reversal of 21378797 is 79787312.

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 21378797 - 2⁶ = 21378733 is a prime.

It is a super-2 number, since 2×21378797² = 914105922334418, 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 (21378767) 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, 422 + ... + 6552.

It is an arithmetic number, because the mean of its divisors is an integer number (2924964).

Almost surely, 2^21378797 is an apocalyptic number.

It is an amenable number.

21378797 is a deficient number, since it is larger than the sum of its proper divisors (2020915).

21378797 is a wasteful number, since it uses less digits than its factorization.

21378797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6459.

The product of its digits is 148176, while the sum is 44.

The square root of 21378797 is about 4623.7211204829. The cubic root of 21378797 is about 277.5413871123.

The spelling of 21378797 in words is "twenty-one million, three hundred seventy-eight thousand, seven hundred ninety-seven".