20778247 has 8 divisors (see below), whose sum is σ = 24136352. Its totient is φ = 17517600.

The previous prime is 20778211. The next prime is 20778253. The reversal of 20778247 is 74287702.

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 20778247 - 2²³ = 12389639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20778287) 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, 23904 + ... + 24757.

It is an arithmetic number, because the mean of its divisors is an integer number (3017044).

Almost surely, 2^20778247 is an apocalyptic number.

20778247 is a deficient number, since it is larger than the sum of its proper divisors (3358105).

20778247 is an equidigital number, since it uses as much as digits as its factorization.

20778247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48729.

The product of its (nonzero) digits is 43904, while the sum is 37.

The square root of 20778247 is about 4558.3162461593. The cubic root of 20778247 is about 274.9178685860.

It can be divided in two parts, 20778 and 247, that added together give a square (21025 = 145²).

The spelling of 20778247 in words is "twenty million, seven hundred seventy-eight thousand, two hundred forty-seven".