20278451 has 4 divisors (see below), whose sum is σ = 20556312. Its totient is φ = 20000592.

The previous prime is 20278441. The next prime is 20278459. The reversal of 20278451 is 15487202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20278451 - 2²² = 16084147 is a prime.

It is a super-2 number, since 2×20278451² = 822431149918802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20278459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138821 + ... + 138966.

It is an arithmetic number, because the mean of its divisors is an integer number (5139078).

Almost surely, 2^20278451 is an apocalyptic number.

20278451 is a deficient number, since it is larger than the sum of its proper divisors (277861).

20278451 is an equidigital number, since it uses as much as digits as its factorization.

20278451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277860.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 20278451 is about 4503.1601126320. The cubic root of 20278451 is about 272.6956807884.

The spelling of 20278451 in words is "twenty million, two hundred seventy-eight thousand, four hundred fifty-one".