21400429949 has 2 divisors, whose sum is σ = 21400429950. Its totient is φ = 21400429948.

The previous prime is 21400429913. The next prime is 21400430083. The reversal of 21400429949 is 94992400412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19999050724 + 1401379225 = 141418^2 + 37435^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400429949 - 2¹² = 21400425853 is a prime.

It is a super-2 number, since 2×21400429949² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21400429849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700214974 + 10700214975.

It is an arithmetic number, because the mean of its divisors is an integer number (10700214975).

Almost surely, 2^21400429949 is an apocalyptic number.

It is an amenable number.

21400429949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400429949 is an equidigital number, since it uses as much as digits as its factorization.

21400429949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 44.

The spelling of 21400429949 in words is "twenty-one billion, four hundred million, four hundred twenty-nine thousand, nine hundred forty-nine".