21151342081 has 32 divisors (see below), whose sum is σ = 23044331520. Its totient is φ = 19341459456.

The previous prime is 21151342061. The next prime is 21151342097. The reversal of 21151342081 is 18024315112.

It is a cyclic number.

It is not a de Polignac number, because 21151342081 - 2⁹ = 21151341569 is a prime.

It is a super-2 number, since 2×21151342081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21151342061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24508656 + ... + 24509518.

It is an arithmetic number, because the mean of its divisors is an integer number (720135360).

Almost surely, 2^21151342081 is an apocalyptic number.

It is an amenable number.

21151342081 is a deficient number, since it is larger than the sum of its proper divisors (1892989439).

21151342081 is a wasteful number, since it uses less digits than its factorization.

21151342081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1233.

The product of its (nonzero) digits is 1920, while the sum is 28.

Adding to 21151342081 its reverse (18024315112), we get a palindrome (39175657193).

The spelling of 21151342081 in words is "twenty-one billion, one hundred fifty-one million, three hundred forty-two thousand, eighty-one".