2778551 has 4 divisors (see below), whose sum is σ = 2797104. Its totient is φ = 2760000.

The previous prime is 2778547. The next prime is 2778583. The reversal of 2778551 is 1558772.

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 2778551 - 2² = 2778547 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 (2778521) 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, 9050 + ... + 9351.

It is an arithmetic number, because the mean of its divisors is an integer number (699276).

2^2778551 is an apocalyptic number.

2778551 is a deficient number, since it is larger than the sum of its proper divisors (18553).

2778551 is a wasteful number, since it uses less digits than its factorization.

2778551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18552.

The product of its digits is 19600, while the sum is 35.

The square root of 2778551 is about 1666.8986171930. The cubic root of 2778551 is about 140.5851528912.

The spelling of 2778551 in words is "two million, seven hundred seventy-eight thousand, five hundred fifty-one".