21145502124 has 72 divisors (see below), whose sum is σ = 53834639040. Its totient is φ = 6998107392.

The previous prime is 21145502123. The next prime is 21145502129. The reversal of 21145502124 is 42120554112.

It is a happy number.

21145502124 is a `hidden beast` number, since 2 + 1 + 145 + 502 + 12 + 4 = 666.

It is a super-2 number, since 2×21145502124² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21145502123) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3074962 + ... + 3081830.

It is an arithmetic number, because the mean of its divisors is an integer number (747703320).

Almost surely, 2^21145502124 is an apocalyptic number.

It is an amenable number.

21145502124 is an abundant number, since it is smaller than the sum of its proper divisors (32689136916).

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

21145502124 is a wasteful number, since it uses less digits than its factorization.

21145502124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7479 (or 7474 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The spelling of 21145502124 in words is "twenty-one billion, one hundred forty-five million, five hundred two thousand, one hundred twenty-four".