2157245640 has 96 divisors (see below), whose sum is σ = 7648430400. Its totient is φ = 522967680.

The previous prime is 2157245539. The next prime is 2157245659. The reversal of 2157245640 is 465427512.

It is a happy number.

2157245640 is a `hidden beast` number, since 2 + 1 + 5 + 7 + 2 + 4 + 5 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2157245595 and 2157245604.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 268420 + ... + 276339.

It is an arithmetic number, because the mean of its divisors is an integer number (79671150).

Almost surely, 2^2157245640 is an apocalyptic number.

2157245640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2157245640 is an abundant number, since it is smaller than the sum of its proper divisors (5491184760).

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

2157245640 is a wasteful number, since it uses less digits than its factorization.

2157245640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544787 (or 544780 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

The square root of 2157245640 is about 46446.1585063824. The cubic root of 2157245640 is about 1292.1111276452. Note that the first 4 decimals are identical.

The spelling of 2157245640 in words is "two billion, one hundred fifty-seven million, two hundred forty-five thousand, six hundred forty".