15421240021 has 8 divisors (see below), whose sum is σ = 16825053888. Its totient is φ = 14017740000.

The previous prime is 15421239979. The next prime is 15421240057. The reversal of 15421240021 is 12004212451.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15421240021 - 2¹³ = 15421231829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15421239974 and 15421240001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15421240061) 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, 30921 + ... + 178321.

It is an arithmetic number, because the mean of its divisors is an integer number (2103131736).

Almost surely, 2^15421240021 is an apocalyptic number.

15421240021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15421240021 is a deficient number, since it is larger than the sum of its proper divisors (1403813867).

15421240021 is a wasteful number, since it uses less digits than its factorization.

15421240021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156923.

The product of its (nonzero) digits is 640, while the sum is 22.

Adding to 15421240021 its reverse (12004212451), we get a palindrome (27425452472).

The spelling of 15421240021 in words is "fifteen billion, four hundred twenty-one million, two hundred forty thousand, twenty-one".