2581218921 has 16 divisors (see below), whose sum is σ = 3643104960. Its totient is φ = 1622832960.

The previous prime is 2581218911. The next prime is 2581218929. The reversal of 2581218921 is 1298121852.

2581218921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2581218921 - 2³¹ = 433735273 is a prime.

It is a super-2 number, since 2×2581218921² = 13325382236256808482, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 2581218921.

It is not an unprimeable number, because it can be changed into a prime (2581218929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 341250 + ... + 348731.

It is an arithmetic number, because the mean of its divisors is an integer number (227694060).

Almost surely, 2^2581218921 is an apocalyptic number.

It is an amenable number.

2581218921 is a deficient number, since it is larger than the sum of its proper divisors (1061886039).

2581218921 is a wasteful number, since it uses less digits than its factorization.

2581218921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 690056.

The product of its digits is 23040, while the sum is 39.

The square root of 2581218921 is about 50805.6977218107. The cubic root of 2581218921 is about 1371.7499298091.

The spelling of 2581218921 in words is "two billion, five hundred eighty-one million, two hundred eighteen thousand, nine hundred twenty-one".