21352121542 has 16 divisors (see below), whose sum is σ = 33263412480. Its totient is φ = 10270801728.

The previous prime is 21352121509. The next prime is 21352121551. The reversal of 21352121542 is 24512125312.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21352121542.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1614438 + ... + 1627609.

It is an arithmetic number, because the mean of its divisors is an integer number (2078963280).

Almost surely, 2^21352121542 is an apocalyptic number.

21352121542 is a deficient number, since it is larger than the sum of its proper divisors (11911290938).

21352121542 is a wasteful number, since it uses less digits than its factorization.

21352121542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3242175.

The product of its digits is 4800, while the sum is 28.

Adding to 21352121542 its reverse (24512125312), we get a palindrome (45864246854).

The spelling of 21352121542 in words is "twenty-one billion, three hundred fifty-two million, one hundred twenty-one thousand, five hundred forty-two".