2557640 has 32 divisors (see below), whose sum is σ = 5892480. Its totient is φ = 998592.

The previous prime is 2557631. The next prime is 2557649. The reversal of 2557640 is 467552.

It is an interprime number because it is at equal distance from previous prime (2557631) and next prime (2557649).

It is not an unprimeable number, because it can be changed into a prime (2557649) 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, 977 + ... + 2463.

It is an arithmetic number, because the mean of its divisors is an integer number (184140).

2^2557640 is an apocalyptic number.

2557640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2557640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2946240).

2557640 is an abundant number, since it is smaller than the sum of its proper divisors (3334840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2557640 is a wasteful number, since it uses less digits than its factorization.

2557640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1541 (or 1537 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 29.

The square root of 2557640 is about 1599.2623299509. The cubic root of 2557640 is about 136.7560259012.

The spelling of 2557640 in words is "two million, five hundred fifty-seven thousand, six hundred forty".