25721418021 has 16 divisors (see below), whose sum is σ = 38206882560. Its totient is φ = 15282751680.

The previous prime is 25721417993. The next prime is 25721418091. The reversal of 25721418021 is 12081412752.

It is not a de Polignac number, because 25721418021 - 2⁶ = 25721417957 is a prime.

It is a super-2 number, since 2×25721418021² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25721418091) 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, 11369965 + ... + 11372226.

It is an arithmetic number, because the mean of its divisors is an integer number (2387930160).

Almost surely, 2^25721418021 is an apocalyptic number.

It is an amenable number.

25721418021 is a deficient number, since it is larger than the sum of its proper divisors (12485464539).

25721418021 is a wasteful number, since it uses less digits than its factorization.

25721418021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22742236.

The product of its (nonzero) digits is 8960, while the sum is 33.

The spelling of 25721418021 in words is "twenty-five billion, seven hundred twenty-one million, four hundred eighteen thousand, twenty-one".