21400351011551 has 16 divisors (see below), whose sum is σ = 21733577376000. Its totient is φ = 21067534591488.

The previous prime is 21400351011547. The next prime is 21400351011577. The reversal of 21400351011551 is 15511015300412.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21400351011551 - 2² = 21400351011547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400351011511) 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, 1659064100 + ... + 1659076998.

It is an arithmetic number, because the mean of its divisors is an integer number (1358348586000).

Almost surely, 2^{21400351011551} is an apocalyptic number.

21400351011551 is a deficient number, since it is larger than the sum of its proper divisors (333226364449).

21400351011551 is a wasteful number, since it uses less digits than its factorization.

21400351011551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26798.

The product of its (nonzero) digits is 3000, while the sum is 29.

Adding to 21400351011551 its reverse (15511015300412), we get a palindrome (36911366311963).

The spelling of 21400351011551 in words is "twenty-one trillion, four hundred billion, three hundred fifty-one million, eleven thousand, five hundred fifty-one".