21122021987 has 8 divisors (see below), whose sum is σ = 23061154032. Its totient is φ = 19186048000.

The previous prime is 21122021971. The next prime is 21122022043. The reversal of 21122021987 is 78912022112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21122021987 - 2⁴ = 21122021971 is a prime.

It is a super-2 number, since 2×21122021987² (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 (21122021927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 775514 + ... + 802287.

It is an arithmetic number, because the mean of its divisors is an integer number (2882644254).

Almost surely, 2^21122021987 is an apocalyptic number.

21122021987 is a deficient number, since it is larger than the sum of its proper divisors (1939132045).

21122021987 is a wasteful number, since it uses less digits than its factorization.

21122021987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1579029.

The product of its (nonzero) digits is 8064, while the sum is 35.

The spelling of 21122021987 in words is "twenty-one billion, one hundred twenty-two million, twenty-one thousand, nine hundred eighty-seven".