21061247364 has 18 divisors (see below), whose sum is σ = 53238153150. Its totient is φ = 7020415776.

The previous prime is 21061247359. The next prime is 21061247369. The reversal of 21061247364 is 46374216012.

21061247364 is a `hidden beast` number, since 2 + 1 + 0 + 612 + 4 + 7 + 36 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21061247359) and next prime (21061247369).

It can be written as a sum of positive squares in only one way, i.e., 14747673600 + 6313573764 = 121440^2 + 79458^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21061247364² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 585034649 = 21061247364 / (2 + 1 + 0 + 6 + 1 + 2 + 4 + 7 + 3 + 6 + 4).

It is not an unprimeable number, because it can be changed into a prime (21061247369) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 292517289 + ... + 292517360.

It is an arithmetic number, because the mean of its divisors is an integer number (2957675175).

Almost surely, 2^21061247364 is an apocalyptic number.

It is an amenable number.

21061247364 is an abundant number, since it is smaller than the sum of its proper divisors (32176905786).

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

21061247364 is a wasteful number, since it uses less digits than its factorization.

21061247364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585034659 (or 585034654 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The spelling of 21061247364 in words is "twenty-one billion, sixty-one million, two hundred forty-seven thousand, three hundred sixty-four".