21125621047 has 16 divisors (see below), whose sum is σ = 23021141760. Its totient is φ = 19304898048.

The previous prime is 21125621021. The next prime is 21125621063. The reversal of 21125621047 is 74012652112.

It is a cyclic number.

It is not a de Polignac number, because 21125621047 - 2¹¹ = 21125618999 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 (21125621347) 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, 266233 + ... + 336349.

It is an arithmetic number, because the mean of its divisors is an integer number (1438821360).

Almost surely, 2^21125621047 is an apocalyptic number.

21125621047 is a deficient number, since it is larger than the sum of its proper divisors (1895520713).

21125621047 is a wasteful number, since it uses less digits than its factorization.

21125621047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70650.

The product of its (nonzero) digits is 6720, while the sum is 31.

The spelling of 21125621047 in words is "twenty-one billion, one hundred twenty-five million, six hundred twenty-one thousand, forty-seven".